applied sciences

Article Roman Fortress Pitiunt: 3D-Reconstruction of the Monument Based on the Materials of Archaeological Research and Geological Paleoreconstructions

Galina Trebeleva 1,* , Konstantin Glazov 1 , Andrey Kizilov 2 , Suram Sakania 3, Vladlen Yurkov 4 and Gleb Yurkov 5

1 Institute of Archaeology, Russian Academy of Sciences, 117292 Moscow, Russia; [email protected] 2 Federal Research Centre, the Subtropical Scientific Centre of the Russian Academy of Sciences, 354000 Sochi, Russia; [email protected] 3 Gulia Abkhaz Institute for Humanitarian Research, Academy of Sciences of Abkhazia, Suhum 384900, Georgia; [email protected] 4 Secondary School 171, 119270 Moscow, Russia; [email protected] 5 N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119334 Moscow, Russia; [email protected] * Correspondence: [email protected]

Abstract: The present study examined the references in the works of ancient authors to the ancient city and the Roman fortress Pitiunt, the geological aspects of the formation of the coastline in the Pitsunda



 Cape area in the first centuries AD and the results of archaeological research of the monument performed from 1952 to 1974. The creation of the 3D reconstruction of the exterior of the Pitiunt Citation: Trebeleva, G.; Glazov, K.; fortress during its prosperity in the IV century AD, along with the churches which were the first Kizilov, A.; Sakania, S.; Yurkov, V.; monuments of religious architecture in northwestern Colchis (northwestern Colchis comprises parts Yurkov, G. Roman Fortress Pitiunt: 3D-Reconstruction of the Monument of the territory of modern Russia, Georgia and Abkhazia) was carried out based on the excavation Based on the Materials of plans and the principles of fortification and temple architecture that were accepted in the late Roman Archaeological Research and times, paying special attention to the geological paleoreconstructions. Geological Paleoreconstructions. Appl. Sci. 2021, 11, 4814. https:// Keywords: Pitiunt fortress; Pontic limes; roman time; 3D reconstruction; geological paleoreconstruction doi.org/10.3390/app11114814

Academic Editors: Mauro Lo Brutto and Valentina Alena Girelli 1. Introduction In the recent decade, 3-D technologies have been widely used in archeology in order to Received: 29 March 2021 protect historical and cultural heritage, aiming at creation of 3D models of various archaeo- Accepted: 20 May 2021 logical sites. The purpose of 3D models is not only to visualize and popularize scientific Published: 24 May 2021 knowledge but also to preserve and present scientific information. Methodologically, two main lines can be noted: fixing the modern condition of archaeological objects, site or Publisher’s Note: MDPI stays neutral exhibits and reconstructing their original appearance. For the first line, various methods, with regard to jurisdictional claims in published maps and institutional affil- for example, photogrammetry [1–7], laser scanning (TLS) [8,9], LiDAR technology [10], etc., iations. are applied when it is necessary to determine and investigate the present 3-D geometry of an object, i.e., to obtain a 3-D image of the current state of an archaeological site or exhibit with the aim of creating a virtual exhibition. The second line comprises the creation of 3-D geometry of a lost or destroyed site based on materials from archaeological research, historical descriptions and analysis of surviving analogies [11–18]. As the output of both Copyright: © 2021 by the authors. described methods, 3-D models used to create virtual reality (VR) in scientific, educational Licensee MDPI, Basel, Switzerland. and exhibition activities can be obtained [8,9,19]. This is consistent with the provisions of This article is an open access article the London Charter [20] distributed under the terms and conditions of the Creative Commons The aims, methods and dissemination plans of computer-based visualization should Attribution (CC BY) license (https:// reflect consideration of how such work can enhance access to cultural heritage that is other- creativecommons.org/licenses/by/ wise inaccessible due to health and safety, disability, economic, political or environmental 4.0/).

Appl. Sci. 2021, 11, 4814. https://doi.org/10.3390/app11114814 https://www.mdpi.com/journal/applsci Appl. Sci. 2021, 11, x FOR PEER REVIEW 2 of 18

Appl. Sci. 2021, 11, 4814 2 of 18

erwise inaccessible due to health and safety, disability, economic, political or environmen- tal reasons or because the object of the visualization is lost, endangered, dispersed or has reasons or because the object of the visualization is lost, endangered, dispersed or has been been destroyed, restored or reconstructed. destroyed, restored or reconstructed. The present study is anan exampleexample ofof thethe secondsecond lineline withwith thethe purposepurpose notnot onlyonly toto demonstrate thethe historicalhistorical sitesite butbut alsoalso toto carrycarry outout historicalhistorical research, research, which which means means study- stud- ingying narrative narrative sources, sources, archival archival data, data, doing doing exploration, exploration, readingreading thethe literatureliterature onon similarsimilar fortressesfortresses andand typestypes ofof militarymilitary campscamps [[10–18]10–18] andand kanabskanabs andand analyzinganalyzing reconstructionreconstruction paleolandscapepaleolandscape [[21].21]. The present work required in-depth analysisanalysis and supportsupport ofof eacheach statement in accordanceaccordance withwith thethe “principle“principle ofof transparency”transparency” toto eliminateeliminate oror minimizeminimize speculative conclusionsconclusions andand decisions.decisions. The Pitiunt Fortress, situated in thethe modernmodern citycity ofof PitsundaPitsunda (Abkhazia),(Abkhazia), alongalong withwith thethe otherother fortificationsfortifications ofof thethe RomanRoman EmpireEmpire suchsuch asas Apsar,Apsar, PhasisPhasis andand Sebastopolis,Sebastopolis, isis one ofof thethe mostmost significantsignificant classicalclassical monumentsmonuments ofof thethe RomanRoman expansionexpansion onon thethe EasternEastern Black Sea coast. The state of modernmodern preservationpreservation compares toto thatthat ofof thethe ApsarApsar fortressfortress whichwhich underwentunderwent severalseveral periodsperiods ofof reconstructionreconstruction andand waswas maintainedmaintained byby thethe OttomanOttoman Empire until 1878, resulting in its present perfect condition. However, the Pitiunt fortress, unlike Apsar, lostlost itsits significancesignificance afterafter thethe 6th6th centurycentury AD,AD, whenwhen itit waswas abandonedabandoned byby thethe garrison, andand sincesince thenthen has has not not been been restored. restored. In In this this regard, regard, at at present, present, the the fortress fortress can can be describedbe described as extended as extended remnants remnants of walls of walls and foundationsand foundations of internal of internal structures, structures, overgrown over- withgrown subtropical with subtropical vegetation, vegetation, which conceal which the conc greatnesseal the ofgreatness the site (Figureof the 1site). Meanwhile, (Figure 1). theMeanwhile, Pitiunt fortress the Pitiunt figured fortress prominently figured inprominently the chain of in Roman the chain fortifications of Roman in fortifications the Eastern Blackin the SeaEastern region Black in the Sea first region centuries in the AD, first and centuries therefore, AD, its and archaeological therefore, its study archaeological is of great intereststudy is forof great the historical interest for and the archeological historical and science. archeological A 3D reconstruction science. A 3D ofreconstruction the exterior of the fortressexterior duringof the fortress its prosperity, during 4thits pros centuryperity, AD, 4th will century highlight AD, thewill significance highlight the of sig- the fortressnificance at of that the time. fortress at that time.

FigureFigure 1.1. TheThe RomanRoman fortressfortress Pitiunt: Pitiunt: ( a()a) localization localization of of the the site; site; (b ()b view) view of of the the site site from from a drone a drone (a red (a red rectangle rectangle marks marks the viewthe viewc of theс of ruinsthe ruins of the of temples; the temples; the yellow the yellow rectangle rectangle marks marks the view the viewd of the d of wall the wewall have we exposed);have exposed); (c) view (c) ofview the of ruins the ofruins the of temples the temples from the from west; the (west;d) Dr. ( A.d) Dr. Kizilov A. Kizilov stands stands on a fragment on a fragment of a stone of a wall stone discovered wall discovered by our by expedition, our expedition, which waswhich not was previously not previously marked marked on the existingon the existing plans of plans the castle. of the castle. Appl. Sci. 2021, 11, 4814 3 of 18

For the purpose of achieving the aim, it is essential to draw a holistic picture of what the ancient city of Pitiunt was like and its position in the political and economic life of the Eastern Black Sea region in the first centuries AD and the reasoning behind locating a Roman fortress in the area. The earliest mention of the ancient city Pitiunt was found in the works of Artemidorus of Ephesus, a famous geographer of the 2nd–1st century BC, quoted by Strabo in his “Geography” (XI, II, 14). Even in those times, Pitiunt was referred to as the “Great”, thus proving the existence of a large city. It is obvious that the city was under the influence of the Pontic Kingdom, whose power was gaining strength at that time. At the same time, it remains unclear whether it was a Greek city since “Pitiunt, unlike Dioscurias or Guenos, was not mentioned in any historical source as a Greek colony or a Greek city; besides, there is no archaeological material from the era of Greek colonization and even in the so-called early antique period” [22]. However, this may also mean that the location of the city is still not defined and is awaiting the right moment. Nevertheless, the ancient Pitiunt from the time of Strabo was an important trade center of the Eastern Black Sea region thus been called “Great” (Strabo XI, II, 14). The political influence of Rome intensified in the 60s of the 1st century, when Nero proclaimed the Black Sea regions as provinces of Rome and brought occupation troops there, as stated in “The Jewish War” (II, 16, 4) written by Josephus. It is possible that Pitiunt suffered a similar fate. In this context, it is important to note that Gaius Pliny Secundus the Elder wrote in his “Historia naturalis” that the Geniochs plundered “the richest city Pithius” (V.16). The epithet “the richest” indicates that Pitiunt was an important economic center at the turn of the era and played an essential role in the trade in the Eastern Black Sea region, attracting barbarians. It is clear that once in the areas of interest of Rome, this important strategic fortification required protection and control of financial flows, demanding constant troop presence. Therefore, it can be assumed that the first Roman fortress of Pitiunt was built in the second half of the 1st century AD after the invasion of the Geniochs. It is possible that before the II century AD it had been made of wood, which explains the absence of finds dating back to that time on the site of Pitiunt. In 134 AD, Pitiunt was mentioned in the work Periplus written by Flavius Arrian, where he wrote “if we move from Dioscurias, the first stop will be in Pitiunt, at a distance of three hundred and fifty stades” (Arr., 27), implying the presence of a harbor or a dock for ships. The location of the harbor will be discussed below. As for the investigated fortress Pitiunt, its construction should be attributed to the times after the writing of “Periplus” by Arrian, i.e., not earlier than the second half of the 2nd century AD. Zosimus, a Byzantine historian of the late 5th–early 6th centuries, in his “New History” described the raids of the “Scythians” (Goths) on Pitiunt in 256–257 AD, mentioning an important detail « Pitiunt was surrounded by a huge wall and had a very convenient harbor” (I, 32–33), which suggests that by the middle of the III century AD, the western part of the fortress had already existed and had been a significant fortification. The building of a Roman fortress in the “Great Pitiunt “was not meant to influence the local rulers but meant as the protection of a large trading center from the barbarians from the north. Historical records representing the role of Pitiunt in the structure of the influence of Rome on the Eastern Black Sea region in subsequent years include the “Church History” of Theodoret, Bishop of Cyrus. While describing the resettlement of John Chrysostom (V century AD), he mentions the location of Pitiunt that “this is the farthest extent of Pontus and Roman power” (V, 34), which means the Pitiunt was a border fortress of the Roman Empire in the diocese of Pontus. References to the “Great Pitiunt” and its fortress found in the works of ancient authors are very scarce. However, they offer an insight into the essential mission that the Pitiunt fortress carried in advancing the interests of the Roman Empire in the Eastern Black Sea region. Appl. Sci. 2021, 11, 4814 4 of 18

2. Materials and Methods In order to accomplish a historical architectural reconstruction, it is essential to study the historical, geological, archaeological and architectural aspects associated with the investigated site [9,23], equally to conducting our own surveys and explorations at the site. This implies: 1. Analysis of available historical evidence about the city and fortress Pitiunt in order to understand its economic, political and military role in the Eastern Black Sea region and determine the chronology of the fortress development in the first centuries AD; 2. Study of materials on the geology of the area for paleoreconstruction of the coastline and landscape of the Pitsunda Cape in the first centuries AD facilitates a deeper understanding of the fortification significance in the period under study and its decline in the subsequent period. This aspect is of crucial importance, since often the modern landscape differs considerably from what it was during the time when the fortress was used. Mainly, the changes in the landscape led to the fact that the fortifications or settlement ceased to function and were abandoned; 3. The use of materials from archaeological research, which are the major source of data about the architecture of the Pitiunt fortress. The combination of archaeological records and analysis of historical evidence would allow to clarify the chronology of the stages of construction of the site; 4. Analysis of the architecture of similar fortifications, civil and religious buildings of the period under study [10–18]. Due to the high degree of architectural standardization in the Roman Empire, especially in construction of fortifications, such analysis enables restoration of the missing archaeological data for the Pitiunt fortress, since firstly, the territory of the fortress had not been explored up to the “mainland” in order not to damage the richest material 3–4 AD discovered during the excavations, and secondly, excavations of only 15% of the territory of the western fortification were done, and therefore, for a full reconstruction of the entire territory of the fortress, it is necessary to turn to research materials from other fortresses of the Empire of the same period; 5. By carrying out our own examinations and reconnaissance on the territory of the fortress, it is possible to check the available archaeological data, correspondingly identifying previously unrecorded sections of walls and structures that are found above the ground due to the continuous process of erosion and weathering. Let us consider in more detail the aforesaid aspects. Issues related to historical sources, which mention the city and fortress of Pitiunt, were discussed in detail in the introduction. As regards the paleoreconstruction of the outlines of the Pitsunda Cape in the 3–4th century AD, the geological studies of the Black Sea coast of the Caucasus, was carried out in the 80s of the 20th century [21], which permitted to model the outlines of the coastline in the fortress area. According to geological studies, in the central part of the peninsula during the Nymphaeum transgression, a brackish lagoon with a strongly indented coastline was formed, occupying a significant part of the Pitsunda Cape, which was fed both from one of the branches of the river Bzyb and networks of smaller rivers of the Musser Upland. It had a channel to the sea in the western part of the cape, plus “in the eastern part of the peninsula in the area of the lake Pitsunda was connected to the water area of the Pitsunda Bay, and was used by the ancient Romans as an internal harbor” [21] (Figure2). Appl. Sci. 2021, 11, 4814 5 of 18 Appl. Sci. 2021, 11, x FOR PEER REVIEW 5 of 18

FigureFigure 2. 2.The The outlinesoutlines ofof thethe coastlinecoastline of the PitsundaPitsunda Cape in the first first century century AD. AD.

Therefore,Therefore, in in thethe firstfirst centurycentury AD,AD, the territoryterritory of the fortress fortress was was located located on on an an island island inin the the delta delta ofof thethe riverriver Bzyb,Bzyb, similarsimilar toto thethe fortificationfortification of of Phasis Phasis in in the the delta delta of of the the Rioni Rioni riverriver [ [23].23]. DuringDuring thethe prosperityprosperity periodperiod of Pitiunt,Pitiunt, the inner inner lagoon lagoon was was located located very very close close toto the the fortress, fortress, whichwhich provided,provided, onon thethe oneone hand,hand, protection from attacks attacks on on the the fortress fortress fromfrom the the land, land, andand onon thethe otherother hand,hand, the convenienceconvenience of docking, docking, loading loading and and unloading unloading thethe ships,ships, etc.etc. As As illustrated illustrated in in Figure Figure 2,2 ,the the fortress fortress was was built built on onthe the southern southern side side of the of thecape, cape, formed formed by a bychannel a channel into the into inner the wate innerrways waterways of the Pitiunt of the harbor Pitiunt and harbor the Pitsunda and the PitsundaBay. The Bay. fortress The fortressguarded guarded the entrance the entrance to the toharbor, the harbor, the complex the complex system system of which of which in- includedcluded the the modern modern lake lake Inkit. Inkit. Between Between the the lake lake and and the thelarge large inner inner harbor harbor adjacent adjacent to the to theMussera Mussera Upland, Upland, there there was was a narrow a narrow strait, strait, controlled controlled by by the the Inkit Inkit Tower Tower in in the the south. south. TheThe PitiuntPitiunt fortressfortress withwith thethe InkitInkit towertower constitutedconstituted one fortificationfortification complex complex guarding guarding thethe accessaccess toto thethe innerinner bay,bay, onon thethe banksbanks ofof which,which, perhaps, traces traces of of the the ancient ancient city city of of PitiuntPitiunt should should bebe searchedsearched for.for. TheThe described picture makes us us reassess reassess these these long-known long-known monumentsmonuments thatthat dodo notnot fitfit intointo thethe modernmodern relief.relief. In this scenario, the the meaning meaning of of the the presencepresence of of “scorpions”,“scorpions”, thethe partsparts of which were found during during archaeological archaeological excavations excavations onon thethe fortressfortress towers,towers, becomesbecomes clearclear [[24,25].24,25]. Apparently, the purpose of of these these catapults catapults waswas aimed,aimed, amongamong otherother targets,targets, atat fightingfighting ships, not only defending the the curtain curtain walls walls fromfrom the the barbarian barbarian infantry.infantry. GeologicalGeological evidenceevidence indicatesindicates that the entrance to to the the harbor harbor from from the the Pitsunda Pitsunda Bay Bay couldcould havehave existedexisted untiluntil thethe 6th6th centurycentury AD, the time of the late late period period of of the the history history of of thethe fortress,fortress, althoughalthough “the“the connectionconnection with the waterways of of the the Pitsunda Pitsunda Bay Bay could could be be preservedpreserved only only on on condition condition of of artificial artificial support support of of the the original original natural natural passage” passage” [ 23[23].]. At At a latera later time, time, the the attenuation attenuation of of the the Nymphaeam Nymphaeam transgression transgression process process led led to to the the drainage drainage of thisof this territory, territory, the the alluvial alluvial coastline coastline in thein th easterne eastern part part of theof the cape, cape, the the desalination desalination of theof lagoonthe lagoon and itsand swamping. its swamping. Presumably, Presumably, these thes factors,e factors, along along with with an outbreakan outbreak of malaria,of ma- werelaria, some were ofsome the reasonsof the reasons the fortification the fortification was abandoned was abandoned in the in 6th the century. 6th century. NowNow letlet usus addressaddress thethe available archaeological materials of the the fortress. fortress. The The findings findings fromfrom archaeologicalarchaeological excavationsexcavations done by the Pitsunda archaeological expedition expedition on on the the territoryterritory ofof thethe fortressfortress fromfrom 19521952 toto 19741974 werewere usedused while developing the the model. model. At At the the beginningbeginning of of thethe investigation,investigation, thethe fortressfortress consistedconsisted of the ruins of of walls walls and and towers towers made made ofof blocksblocks ofof aa marinemarine conglomerate,conglomerate, about a meter high, which are are now now separated separated by by a a concreteconcrete beltbelt fromfrom thethe wallswalls thatthat werewere erected during the restoration work work of of the the 70s 70s of of thethe twentieth twentieth century.century. TheThe totaltotal areaarea ofof thethe fortificationfortification is about about 6.5 6.5 hectares, hectares, the the length length of of thethe outerouter wallswalls isis 12001200 m,m, thethe totaltotal numbernumber of identifiedidentified outer outer towers towers is is 27 27 (only (only 4 4 have have been excavated). During the twenty-two years of the expedition, twenty-one excavations Appl. Sci. 2021, 11, 4814 6 of 18

were laid with a total area of about one hectare. Although this makes up about fifteen per cent of the entire inner area of the fortress, the study made possible to reveal the outlines of residential and administrative buildings, garrison and thermal baths attached to the eastern side of the first castellum, together with a multi-layered church complex on the territory of the eastern fortification called canaba. The result of this work was obtaining the general plan of the fortification, published for the first time in 1975 [26], which formed the basis for our 3D reconstruction of the fortress. A joint analysis of the general plan and historical information about the city and the fortress of Pitiunt allowed us to gain essential data about the chronology of the monument and the stages of its development. The general plan shows that the fortified part of the Great Pitiunt consists of three main parts (Figure3). Appl. Sci. 2021, 11, x FOR PEER REVIEW 6 of 18 1. The western part which is the castellum is the earliest classic Roman castellum 155 × 130 m with a central street along the East–West axis, starting at the eastern gate formed by a protruding double tower, and ending at the praetorium in the western beenpart excavated). of the castellum. During the Narrow twenty-two lanes year derives of the from expedition, the main twenty-one street in both excavations directions werewith laid symmetricallywith a total area located of about structures one hectare. for variousAlthough purposes this makes built up inabout accordance fifteen per with centstrict of the regulation entire inner and area rules of the of thefortress, Roman the fortification study made architecture, possible to reveal related the to outlines castellum of residential(Figure3a). and administrative buildings, garrison and thermal baths attached to the 2.easternThe side central of the part first is thecastellum, space betweentogether thewith eastern a multi-layered wall of the church castellum complex and on another the territorywall parallelof the eastern to it, atfortification a distance called of 75 mcanaba. to the east. This area is a later expansion of the castellumThe result to of the this east, work which, was obtaining apparently, the hadgeneral not plan been of completed the fortification, (Figure published3b). 3.for theThe first eastern time partin 1975 canaba [26], iswhich semicircular; formed the it basis was builtfor our later, 3D reconstruction and it varies fromof the the fortress.western A joint part analysis not only of inthe the general shape plan but alsoand historical in the thickness information of the about walls, the the city length and of the fortressthe curtain of Pitiunt walls, allowed i.e., in the us easternto gain e part,ssential the data walls about are thinner,the chronology and the of curtain the mon- walls umentare and shorter the stages (Figure of3 itsc). development. The general plan shows that the fortified part of the Great Pitiunt consists of three main parts (Figure 3).

FigureFigure 3. General 3. General plan plan of of Pitiunta Pitiunta fortress, fortress, adapted adapted fromfrom ref.ref. [[26]:26]: a—castellum (end (end of of II–beginning II–beginning of ofIII IIIcenturies centuries AD); AD); b—expansionb—expansion of theof the castellum castellum to to the the east east (middle (middle of of the the 3rd3rd centurycentury AD); c—canaba (late (late III–mid III–mid IV IV centuries centuries AD). AD).

1. InThe addition western to part excavation which is plans,the castellum we examined is the earliest the entire classic accessible Roman castellum territory 155 of × the site, which130 m made with ita possiblecentral street to clarify along and the supplement East–West theaxis, available starting material.at the eastern Therefore, gate in formed by a protruding double tower, and ending at the praetorium in the western part of the castellum. Narrow lanes derive from the main street in both directions with symmetrically located structures for various purposes built in accordance with strict regulation and rules of the Roman fortification architecture, related to castellum (Figure 3a). 2. The central part is the space between the eastern wall of the castellum and another wall parallel to it, at a distance of 75 m to the east. This area is a later expansion of the castellum to the east, which, apparently, had not been completed (Figure 3b). 3. The eastern part canaba is semicircular; it was built later, and it varies from the west- ern part not only in the shape but also in the thickness of the walls, the length of the curtain walls, i.e., in the eastern part, the walls are thinner, and the curtain walls are shorter (Figure 3c). Appl. Sci. 2021, 11, 4814 7 of 18

particular, a fragment of a stone wall about eight meters long not marked on the existing plans of the castellum was revealed (Figure1d). It is located outside the east wall of the castellum, midway between tower 4 and the eastern gate. Having a thickness of about eighty centimeters in the above-ground part, the wall stretches at a right angle towards the canaba. It is probable that during the archaeological excavations carried out by the Pitsunda archaeological expedition on the territory of the fortress from 1952 to 1974, this area could have been located deep in the thickets under a layer of humus and was not visible. Obviously, after clearing the territory of the fortress from thickets for further use by the tourist industry, the bush was cut down, and the humus was washed away by the abundant precipitation for the region, exposing the contours of the wall. We believe that future archaeological excavations and analysis of the composition of the limestone solution of the wall will assist to date this site, as was earlier the case with dating the Kelasur wall, an important historical site of the region [27]. At the moment, we can only assume that it had been either an unfinished part of the second stage of construction of the fortress, or the remains of the tower of the first castellum, a symmetrical tower number 14, which was later dismantled for materials for the construction of a canab. All these parts comprise a single fortification, but they are of different times. Based on the excavations results, the chronology of the monument is the following: • At the end of the 2nd–beginning of the 3rd century a classic Roman castellum of rectangular shape was built (Figure3a); • In the middle of 3rd century, the castellum was expanded to the east (Figure3b), which most likely coincided with a series of barbarian invasions in the second half of the 50s of the 3rd centuries when the fortress was captured, destroyed and burned, and the garrison were killed; • At the end of 3rd–4th centuries AD, the fortress was restored, and the eastern part of the fortification (canaba) was constructed (Figure3c); it was the prosperity pe- riod of the fortress, and the first Christian churches were built in the territory of northwestern Colchis; • The 5th century AD was the period of the city’s decline; • The first half of the 6th century was the era of Justinian and the second flourishing of Pitiunt; • In the middle of the 6th century, the fortress was abandoned by the garrison before the invasion of Mermeroy, and the life in the city faded; • The second half of the 6th century was the flourishing of the fortress as a Christian center of early medieval Abazgia. 3D reconstruction of the appearance of the Roman fortress Pitiunt as of the 4th century AD was carried out based on the abovementioned chronology and the plans for the fortification obtained in the course of excavations. This time period was targeted specifically since it is the heyday of Pitiunt which is proved by overwhelming number of findings on the site of the fortress. By that time, the construction of the entire complex of fortifications had been completed and the first Christian churches had been built in the territory of northwestern Colchis. As mentioned above, the excavations revealed mainly the central part of the western fortification, which is not sufficient to fully visualize of the object; therefore, this recon- struction is impossible without an analysis of the architecture and planning of Roman fortifications of the 3–4 centuries AD. This is facilitated by abundant research into this aspect and the large quantity of material on 3D reconstruction of similar sites [10–18]. Since the fortification on the territory of the Roman Empire was largely standardized, in our case, the choice of method of reconstruction by analogy can be quite justified, at least for the territory of the castellum, especially since we do not pursue the aim of creating a detailed reconstruction of the object due to insufficient preservation and archaeological study of the site, and we strive to convey the general view of the fortress, inscribed in the ancient landscape. Appl. Sci. 2021, 11, 4814 8 of 18

Moreover, in some places, i.e., in the northern part of the canaba (Figure3c), due to the lack of archaeological data, when reconstructing a section of the wall, it was required to proceed from the general principles of fortification while maintaining the distances between the towers, which corresponds to the general architecture of the fortress. In those areas where there was no archaeological material available, we created the model based on analogies with other fortifications, using the principles and rules of fortification and general architectural and construction considerations. Abovementioned are the main aspects and principles that were used in the present work. At each stage, we were guided by the “principle of transparency” defined by the London Charter [21] and more specifically, in the field of archeology, the Seville Princi- ple [28]. However, we did not use the color scale to display historical and archaeological evidence, as suggested by a number of experts [29]. In our opinion, such a multi-colored model will lose its visibility and will be incomprehensible to most users Let us consider the methods used in the reconstruction. The fortress model was created in Autodesk 3ds Max using polygonal modelling. As a basis for modeling, a plane was taken with a superimposed scaled general plan of Pitiunt Fortress, obtained from the results of excavations in 1952–1974. Each element of the fortress (section of the wall, tower) was outlined along the contour on the plan, adjusted according to the descriptions of the Pitsunda expedition [30] and stretched at the required height (Figure4). The height of the walls was determined by the length of the base of the stone stairs running along the fortress walls in the area of towers No. 2 and 5, identified by the Pitsunda expedition. Their length is 7.5–8 m. with a tread depth of 30 cm; the total number of steps totals about 25, which with a step height of 20 cm determines the height of the wall of about 5 m and is consistent with the height of the walls of the perfectly preserved Roman fortress Apsar, built at the same time as Pitiunt and which had a similar purpose, size and number of towers [30]. The height of the parapet was taken as standard for fortifications of that time as 2 m and the height of the embrasure base at 1 m. The widths of the merlons and embrasures were taken as typical for late Roman fortresses of 2 and 1 m, respectively [8]. Having studied the nature of the stone stairs leading to the walls in the area of towers No. 2 and 5, we found that by the first staircase it was possible only to get to the wall between towers 2 and 11, and the passage towards the canaba was blocked by two wide breaks in the base of the stairs at 3, 5 m, over which the drawbridges were probably lowered. The second staircase led to the center of the fan-shaped tower No. 5, probably indicating that access to the walls was limited by doors in the upper level of tower No. 5. Based on this, we concluded that the towers of the fortress had to rise above the walls by one level and prevent free passages between curtains, which we kept in the model. The height of the upper platform of the tower was made 7.5 m in order to ensure a minimum required height in the interior, taking into account the beams and the ceiling. The texture of the masonry the blocks of the sea conglomerate was implied on the fortress walls and towers, photographs of which were made by our team during exploration of the existing sections of the fortress wall. The structure of the towers in the model was made with Opus Mixtum masonry, which does not contradict the results of our investigation of the site. A belt of similar masonry was found in the surviving fragments of the walls of Tower No. 5. After building the geometry of the fortress, a landscape was created on the basis of a paleoreconstruction of the terrain made according to [21]. In order to do so, a scaled map was imposed on a 1x1 km plane of the southern tip of the Pitsunda Cape, during the period of the 3rd–4th centuries AD was produced, partially including both the seaside coastline and the internal outlines of the Pitsunda harbor, where the fortress was located. We placed two planes above it, creating the water surface and the terrain. The terrain plane was converted to a polygonal surface and deformed by extrusion according to the coastline map. In the area of the fortress, the polygonal mesh was made finer to ensure greater accuracy. The terrain was combined with the fortress and adjusted in place; a moat was modeled around the fortress, getting the water from the Pitsunda harbor. Appl. Sci. 2021, 11, 4814 9 of 18 Appl. Sci. 2021, 11, x FOR PEER REVIEW 9 of 18

FigureFigure 4. 4. StagesStages of of modeling: modeling: ( (aa)) creating creating the the outlines outlines of of walls walls and and towers; towers; ( (bb)) raising raising the the contours contours of of the the walls walls to to a a certain certain height; (c,d) texture mapping; (e) creation of internal planning; (f) reconstruction of small artistic details. height; (c,d) texture mapping; (e) creation of internal planning; (f) reconstruction of small artistic details.

TheTrees texture and shrubs of the have masonry been addedthe blocks to the of scene the sea in combinationconglomerate with was different implied textures on the fortressof the underlying walls and surfacetowers, andphotographs haze in order of whic to increaseh were themade realistic by our perception team during of the explora- model. tion ofThese the existing were the sections methods of the and fortress considerations wall. The appliedstructure in of the the reconstruction towers in the model of the wasexterior made of with the Roman Opus Mixtum fortress ofmasonry, Pitiunt. which does not contradict the results of our in- vestigation of the site. A belt of similar masonry was found in the surviving fragments of the3. Results walls of Tower No. 5. AfterArchaeological building the work geometry carried of out the on fortress, the territory a landscape of the was Pitsunda created Cape on the revealed basis of two a paleoreconstructionfortifications dating of back the toterrain the late made Roman according time: theto [21]. Pitiunt In order fortress to do and so, the a scaled Inkit tower, map wasexisting imposed in the on same a 1x1 period.km plane Considering of the southern these tip objects of the inPitsunda the modern Cape, landscape,during the itpe- is rioddifficult of the to 3rd–4th understand centuries their fortificationAD was produced, purpose, partially since the including fortress isboth located the seaside in the depthscoast- lineof the and cape theat internal the bank outlines of the swamp,of the Pitsunda and the harbor, tower is where in the the center fortress of the was cape located. on the bank of theWe boggy placed lake two Inkit. planes Having above beenit, creating built in the such water a location, surface and they the could terrain. not The be used terrain for planeprotection was converted of anything. to Consideringa polygonal thesurface high an fortificationd deformed art by of extrusion the Romans, according this choice to the of coastlinea place for map. fortifications In the area seems of the more fortress, than bizarre.the polygonal mesh was made finer to ensure greaterHowever, accuracy. the The performed terrain was paleoreconstruction combined with the setsfortress a new and focus adjusted on thisin place; fortification a moat wascomplex, modeled which around played the an fortress, important getting role in the the water defense from and the control Pitsunda of the harbor. territory. Fortress PitiuntTrees protected and shrubs from have the enemybeen added the entrance to the scene from in thecombination sea to a convenient with different inner textures harbor oflocated the underlying on the site ofsurface present-day and haze Inkit in Lake, order and to theincrease Inkit Towerthe realistic was probably perception designed of the to model.control a narrow passage to the harbor from a large inland bay (Figure2). On the shores of thisThese bay, were perhaps the methods the ancient and city considerations of Pitiunt should applied be in sought. the reconstruction One method of ofthe such ex- terior of the Roman fortress of Pitiunt. Appl. Sci. 2021, 11, x FOR PEER REVIEW 10 of 18

3. Results Archaeological work carried out on the territory of the Pitsunda Cape revealed two fortifications dating back to the late Roman time: the Pitiunt fortress and the Inkit tower, existing in the same period. Considering these objects in the modern landscape, it is diffi- cult to understand their fortification purpose, since the fortress is located in the depths of the cape at the bank of the swamp, and the tower is in the center of the cape on the bank of the boggy lake Inkit. Having been built in such a location, they could not be used for protection of anything. Considering the high fortification art of the Romans, this choice of a place for fortifications seems more than bizarre. However, the performed paleoreconstruction sets a new focus on this fortification complex, which played an important role in the defense and control of the territory. For- tress Pitiunt protected from the enemy the entrance from the sea to a convenient inner harbor located on the site of present-day Inkit Lake, and the Inkit Tower was probably designed to control a narrow passage to the harbor from a large inland bay (Figure 2). On the shores of this bay, perhaps the ancient city of Pitiunt should be sought. One method of such protection could be the pulling of a chain from the Inkit Tower, blocking the exit to the sea from the inner bay, which provided an important tool to influence the local population. Appl. Sci. 2021, 11, 4814 10 of 18 It must be understood that the Pitiunt fortress in the 3–4 centuries was not just an- other internal fortification in the network of the Black Sea Limes but a border outpost,

where the lands of theprotection barbarians could bebegan, the pulling so its of virtual a chain fromreconstruction the Inkit Tower, is of blocking particular the exit inter- to the sea est. from the inner bay, which provided an important tool to influence the local population. Excavations of theIt Pitsunda must be understood archaeological that the Pitiuntexpedition fortress have in the exposed 3–4 centuries almost was not the just en- another tire perimeter of theinternal fortress fortification walls, with in the th networke exception of the Blackof the Sea northern Limes but wall a border of the outpost, canaba, where the since their current locationlands of the is a barbarians swamp began,(Figure so 3c). its virtual Analysis reconstruction of geological is of particular data shows interest. that Excavations of the Pitsunda archaeological expedition have exposed almost the entire the harbor of the “Greatperimeter Pitiunt” of the fortressapproached walls, withthe fortress the exception in this of thevery northern place. wallPrior of to the the canaba, excavations, severalsince scientists their current had suggested location is ath swampat the (Figureeastern3c). part Analysis of the of semicircular geological data for- shows tification was the innerthat theport harbor of the of fortress. the “Great However, Pitiunt” approached the study the of fortressthe site in between this very place.Towers Prior to No.1 and 2, with a lengththe excavations, of about several160 m, scientists revealed had the suggested presence that of the fragments eastern part of ofthe the fortress semicircular fortification was the inner port of the fortress. However, the study of the site between wall along the entireTowers length No.1 immersed and 2, with in a lengtha swamp of about [31]. 160 m, revealed the presence of fragments of the Due to the waterlogging,fortress wall alongnot a the single entire tower length immersedwas identified. in a swamp According [31]. to Apakidze A.M., there should be fewerDue to than the waterlogging, 6–7 of the nottowers. a single Proceeding tower was identified. from this According and from to Apakidzethe fact that there were A.M.,no main there gates should on be the fewer clea thanred 6–7sections of the towers.of the walls Proceeding of the from canaba, this and it was from the assumed that they couldfact that have there been were in no the main midd gatesle on of the the cleared northern sections wall of theentering walls of the the canaba,harbor. it was assumed that they could have been in the middle of the northern wall entering the harbor. By analogy with theBy eastern analogy gates with the of eastern the ca gatesstellum of the (Figure castellum 5) (Figure and other5) and Roman other Roman fortresses fortresses of of the 3rd–4th centuries,the 3rd–4th they centuries, could have they couldrepresented have represented a double a double D-shaped D-shaped tower, tower, with with an an arch arch of the gate in betweenof the gate (Figure in between 6). (Figure6).

Figure 5. East gate of castellum.

On the northeastern corner of the wall, according to the general principles of Roman fortification, we placed the corner tower, and the remaining space of the northern wall of the canaba was filled with middle towers based on the average length of the curtain walls of the eastern part of the fortification. There were four missing towers in total, which does not oppose the theory of Apakidze A.M. The walls of the fortress, by analogy with other Roman fortifications of that time, were probably surrounded by a defensive moat along the perimeter, which had breaks only in the gate, which was shown in the model. According to the results of the excavations of Tower No. 1, the construction of the canaba wall belongs to the period of our reconstruction since an early layer with red- lacquered utensils typical of the 3rd–4th centuries was found [31]. Appl. Sci. 2021, 11, x FOR PEER REVIEW 11 of 18

Appl. Sci. 2021, 11, 4814 11 of 18

Figure 5. East gate of castellum.

Figure 6. ReconstructionFigure 6. ofReconstruction the northern wall of the of area northern 3 (canabas) wall of. area 3 (canabas).

On the northeasternIn relation corner to of the the shape wall, of a theccording castellum to the itself, general it can principles be assumed of Roman that it had survived at fortification, weleast placed two the periods corner of construction:tower, and the in remaining the beginning space (late of second–earlythe northern wall third of centuries AD), it the canaba waswas filled a rectangularwith middle classic towers Roman based castellumon the average measuring length 130 of ×the155 curtain m, formed walls by four corner of the eastern parttowers of the and fortification. twelve middle There towers. were four The missing east corner towers towers in total, appear which to have does been rebuilt in not oppose thethe theory second of Apakidze construction A.M. period The walls at the of time the whenfortress, the by castellum analogy waswith expanded other to the east. Roman fortificationsThis is of evidenced that time, by were the wall,probably uncovered surrounded by the by excavations, a defensive which moat runsalong from Tower No. the perimeter, which2 to the had south, breaks parallel only in to the the gate, eastern which wall was of theshown castellum. in the model. It was erected to the east by According75 to m, the increasing results of the the size excavations of the fortress of Tower to 130 No.× 2301, the m. construction According to of A.M. the Apakidze, the canaba wall belongsexpansion to the of period the castellum of our reco tooknstruction place in since the second an early half layer of with the 3rd red-lac- century [30]. If we quered utensilscorrelate typical of this the with 3rd–4th the events centuries of the was second found. half [31] of the 50s of the 3rd century AD, described In relationby to Zosimus,the shape it of can the be castellum assumed itse thatlf, the it can restructuring be assumed of that the fortressit had survived could have begun after at least two periodsthe Goths of construction: were repelled in by the Sukessian beginning in 256,(late but second–early the restructuring third hadcenturies not been completed AD), it was a rectangularuntil the fall classic of the Roman fortress castellum in the second measuring wave of130 the × 155 invasion. m, formed The towersby four of the northern corner towers andwall twelve indirectly middle prove towers. the rebuilding The east corner of the castellum.towers appear The generalto have planbeen showsre- that Tower built in the secondNo. 2construction was planned period to be theat the corner timetower, when andthe castellum tower No. was 9 was expanded for the centralto one, since the east. This isit evidenced is larger than by the towers wall, No. unco 7,vered 8, 10 andby the 11. excavations, Tower No. 4 which was preserved runs from in the southern Tower No. 2 tosection the south, of theparallel corner, to the and easter Towern wall No. 16of the in the castellum. central one.It was The erected number to the of towers on the east by 75 m, increasingnorthern andthe size southern of the wallsfortress of castellum,to 130 × 230 along m. According with the asymmetry to A.M. Apaki- of towers 9 and 16 dze, the expansionrelating of the to castellum the main took axis ofplace the in fortification, the second indicatehalf of the that 3rd the century northern [30]. wall If was rebuilt; we correlate thisthe with building the events of the of eastern the second wall washalf started;of the 50s however, of the 3rd there century was insufficient AD, de- time to start scribed by Zosimus,rebuilding it can the be southern assumed wall that of the the restructuring castellum. of the fortress could have begun after the GothsIt is were possible repelled that atby the Suke endssian of the in 3rd256, century, but the during restructuring the restoration had not and reconstruc- been completedtion until of the the fall fortress, of the the fortress was noin the necessity second to wave complete of the the invasion. eastern The part towers of the castellum due of the northernto wall the constructionindirectly prove of the the canaba. rebuilding Simultaneously, of the castellum. the remaining The general eastern plan wall was used to shows that Towerseparate No. 2 thewas territory planned from to be the the canaba. corner Garrisontower, and baths tower were No. revealed 9 was for during the excavations, central one, sincetogether it is larger with warehouses,than towers No. cattle 7, pens,8, 10 and workshops, 11. Tower etc. No. (Figure 4 was7). preserved in the southern section of the corner, and Tower No. 16 in the central one. The number of towers on the northern and southern walls of castellum, along with the asymmetry of towers 9 and 16 relating to the main axis of the fortification, indicate that the northern wall was rebuilt; the building of the eastern wall was started; however, there was insufficient time to start rebuilding the southern wall of the castellum. It is possible that at the end of the 3rd century, during the restoration and reconstruc- tion of the fortress, the was no necessity to complete the eastern part of the castellum due to the construction of the canaba. Simultaneously, the remaining eastern wall was used to separate the territory from the canaba. Garrison baths were revealed during excavations, together with warehouses, cattle pens, workshops, etc. (Figure 7). Appl. Sci. 2021, 11, 4814 12 of 18 Appl. Sci. 2021, 11, x FOR PEER REVIEW 12 of 18

Appl. Sci. 2021, 11, x FOR PEER REVIEW 12 of 18

FigureFigure 7.7. Reconstruction of of the the central central pa partrt of of the the fortress fortress (area (area 2). 2). Figure 7. Reconstruction of the central part of the fortress (area 2). ItIt alsoalso servedserved as as a a buffer buffer zone zone between between the the canaba canaba and and the the first first castellum-citadel castellum-citadel in in thethe eventeventIt also ofof served enemy as seizing seizing a buffer the the zone eastern eastern between part part of the of the thecanaba fortress. fortress. and Since the Since firstthe the excavationscastellum-citadel excavations did didnot in not revealrevealthe event aa sectionsection of enemy of the theseizing wall wall theenclosing enclosing eastern area part area 2 of 2from fromthe fortress.the the south, south, Since it can it the can be excavations beassumed assumed that did that thisnot this sectionsectionreveal a waswas section made of with withthe walla a wooden wooden enclosing palisade palisade area with 2 with from towers towers the south,and and gates, it gates, can which be which assumed is often is often foundthat found this in in section was made with a wooden palisade with towers and gates, which is often found in thethe structuresstructures of Roman fortifications fortifications (Figure (Figure 8).8). the structures of Roman fortifications (Figure 8).

Figure 8. Reconstruction of area 2 behind the eastern wall of the castellum with garrison baths, andFigure buildings 8. Reconstruction for various of purposes. area 2 behind the eastern wall of the castellum with garrison baths, Figure 8. Reconstruction of area 2 behind the eastern wall of the castellum with garrison baths, and and buildings for various purposes. buildingsThe forreconstruction various purposes. of the western wall of the castellum is of special interest. It is formedThe by reconstruction five towers (No. of the5, 14, western 13, 12 andwall 6). of The the fan-shapedcastellum isform of special of towers interest. No. 5 Itand is The reconstruction of the western wall of the castellum is of special interest. It is 6formed is typical by fiveto the towers era of (No. Emperor 5, 14, 13,Constantin 12 and 6).e andThe later,fan-shaped and therefore, form of towersperhaps, No. we 5 andcan formed by five towers (No. 5, 14, 13, 12 and 6). The fan-shaped form of towers No. 5 and find6 is typicala later toreconstruction the era of Emperor of the fortress.Constantin Inspectione and later, of theseand therefore,towers revealed perhaps, that we they can 6 is typical to the era of Emperor Constantine and later, and therefore, perhaps, we can werefind aattached later reconstruction to the rounded of the corners fortress. of theInspection fortress ofwall, these distinctive towers revealed of earlier that Roman they find a later reconstruction of the fortress. Inspection of these towers revealed that they fortifications.were attached Tower to the No.rounded 13, located corners in ofthe the center fortress of the wall, western distinctive wall, isof largerearlier than Roman the were attached to the rounded corners of the fortress wall, distinctive of earlier Roman others,fortifications. “therefore, Tower it canNo. be13, assumedlocated in that the it center defended of the the western large western wall, is gate...larger thethan 13th the fortifications.tower,others, in“therefore, terms Tower of itits can No.location be 13,assumed and located strength that in it the ofdefended centerstructure, ofthe themust large western have western been wall, gate... the is main largerthe 13th en- than thetrance—thetower, others, in terms “therefore,portico of itsof castellum”location it can be and [32] assumed strength (Figure that of9). structure, it defended must the have large been western the main gate... en- the 13thtrance—the tower, inportico terms of of castellum” its location [32] and (Figure strength 9). of structure, must have been the main entrance—the portico of castellum” [32] (Figure9). Appl. Sci. 2021, 11, 4814 13 of 18 Appl. Sci. 2021, 11, x FOR PEER REVIEW 13 of 18

Figure 9. Reconstruction of the western gate of the fortress. Figure 9. Reconstruction of the western gate of the fortress.

TheThe reconstructionreconstruction of of the the inner inner part part of of the the castellum castellum was was carried carried out out based based on the on the researchresearch ofof the Pitsunda archaeological archaeological expediti expeditionon done done in inexcavations excavations V, VI, V, VI,IX, IX,XIII, XIII, XVI, XVI, XVII, XVIII, XIX, together with analogies with the already studied and reconstructed Ro- XVII, XVIII, XIX, together with analogies with the already studied and reconstructed Roman man fortifications of the III–IV centuries AD. The fact that the structure of Roman fortifi- fortifications of the III–IV centuries AD. The fact that the structure of Roman fortifications cations at that time was standard and followed the same planning rules facilitated the at that time was standard and followed the same planning rules facilitated the task. task. In the central place of the castellum, there is praetorium building located in the western In the central place of the castellum, there is praetorium building located in the west- part of the fortification at the end of the central street, which stretches from the eastern gate ern part of the fortification at the end of the central street, which stretches from the eastern along the E–W axis (Figures 10–12). On both sides of the street, there are residential and gate along the E–W axis (Figures 10–12). On both sides of the street, there are residential administrativeand administrative buildings, buildings, three three of which of which have have at leastat least thermal thermal baths. baths.

Figure 10. General view of the castellum from the eastern gate. Figure 10. General view of the castellum from the eastern gate. Appl. Sci. 2021, 11, 4814 14 of 18 Appl. Sci. 2021, 11, x FOR PEER REVIEW 14 of 18 Appl. Sci. 2021, 11, x FOR PEER REVIEW 14 of 18

Figure 11. General view of castellum from the northwest. FigureFigure 11.11.General General viewview ofof castellumcastellum fromfrom the the northwest. northwest.

Figure 12. Reconstruction of the general view of the fortress “Great Pitiunt”. Figure 12. Reconstruction of the general view of the fortress “Great Pitiunt”. FigureArmories, 12. Reconstruction warehouses, of the a hospital, general view stables, of the et fortressc. needed “Great to bePitiunt”. placed inside the fortress. In the proposed model, the opinion of A. M. Apakidze that all relatively important struc- turesArmories,Armories, of the “Great warehouses, warehouses, Pitiunt” were a a hospital, hospital, covered stables, stables, with tiles etc. etc. at neededneeded one time toto bewasbe placedplaced taken insideintoinside considera- thethe fortress.fortress. InIntion. thethe The proposedproposed lower model,partmodel, of theallthe buildings opinionopinion ofofin A. A.th M.eM. 3D ApakidzeApakidze model was thatthat “plastered” allall relativelyrelatively with importantimportant cementum struc-struc- turestures(lime-based of of the the “Great plasters“Great Pitiunt” Pitiunt” with fine were were ground covered covered brick with content),with tiles tiles at since oneat one timethis time technique was was taken taken was into usedinto consideration. considera-by the Thetion.Romans lower The everywhere partlower of allpart buildings to of protect all buildings in against the 3D inmois model thture,e 3D was andmodel “plastered” A.M. was Apakidze “plastered” with cementum noted with the (lime-basedappear- cementum plasters(lime-basedance of withthe plasterslime-based fine ground with plasters fine brick ground content),with brickfine since groundcontent), this brick technique since content—cementum this wastechnique used bywas the usedin Romansvast by the everywhereRomansamount. everywhere to protect to against protect moisture, against andmois A.M.ture, Apakidzeand A.M. notedApakidze the appearancenoted the appear- of the lime-basedance Theof spacethe plasters lime-based around with the fine plasterspraetorium ground with brickalong fine content—cementum the ground northern, brick western content—cementum in and vast southern amount. walls in of vast amount.the castellumThe space was around not excavated the praetorium by the expedi alongtion, the but northern, by analogy western with other and southern Roman for- walls oftresses theThe castellum of spacethat time, around was barracks not the excavated praetorium could have by thealongbeen expedition, located the northern, here. but When bywestern analogy modeling and with southern this other site, Romanbar-walls of fortressestheracks castellum were of built that was according time, not excavated barracks to the couldRoman by the have expedistandard, beention, locatedincluding but by here. analogy 20 rooms When with for modeling 4other people Roman thiswith site, for- barrackstressestwo bunk of were thatbeds builttime, and a accordingbarracks room for could toa centurion the have Roman been (sin standard, celocated the number here. including When of centuria 20modeling rooms in the forthis 3rd–4th 4 site, people bar- withrackscenturies two were was bunk built 80 beds people).according and The a to room designatedthe Roman for a centurionsp standard,ace accommodates (since including the up number20 torooms 10 barracks, of for centuria 4 people which in with the 3rd–4thtwomakes bunk it centuries possible beds and wasto estimatea 80room people). forthe asize Thecenturion of designated the military (since space the garrison number accommodates at 500–800of centuria uppeople, toin 10the which barracks, 3rd–4th whichcenturies makes was it 80 possible people). to The estimate designated the size space of theaccommodates military garrison up to at10 500–800barracks, people, which whichmakes corresponds it possible to to estimate one Roman the size cohort. of the As military is known, garrison the vexillation at 500–800 of thepeople, XV legionwhich “Apollinaris” was quartered in Pitiunt, the symbols of the legion were found on bricks and clay slabs during excavations of the fortress and the area [33]. Appl. Sci. 2021, 11, x FOR PEER REVIEW 15 of 18

Appl. Sci. 2021, 11, 4814 15 of 18 corresponds to one Roman cohort. As is known, the vexillation of the XV legion “Apolli- naris” was quartered in Pitiunt, the symbols of the legion were found on bricks and clay slabs during excavations of the fortress and the area [33]. TheThe territory territory of of the the canaba canaba was was not not excavatedexcavated byby PitsundaPitsunda archaeologicalarchaeological expedition, expedition, withwith the the exception exception ofof excavations excavations IIIIII andand XX;XX; therefore, therefore, it it was was not not reconstructed reconstructed in in the the model,model, in in order order not not to to be be too too speculative. speculative. Nevertheless,Nevertheless, it it isis clearclear thatthat residentialresidential quarters, quarters, retailretail space, space, warehouses, warehouses, inns inns and and other other infrastructure infrastructure elements elements of such of ansuch important an important trade andtrade economic and economic center ofcenter the Easternof the Eastern Black Sea Blac regionk Sea region as Pitiunt as Pitiunt were located were located here. here. OfOf particular particular importance importance is is the the visualization visualization of of the the appearance appearance of of the the Pitiunt Pitiunt churches churches locatedlocated in in the the territory territory of of the the canaba canaba (Figure (Figure1 ),1), since since they they are are the the first first churches churches built built in in northwesternnorthwestern Colchis. Colchis. ChurchChurch No.No. 1 1 is is the the oldest. oldest. It is It a is one-nave a one-nave hall hall building building with with a semicircular a semicircular apse apse[34,35].[34 ,It35 is]. believed It is believed to have to havebeen beenerected erected before before 313–332. 313–332. and was and the was cathedral the cathedral of the ofBishop the Bishop of Pitiunt of Pitiunt Stratophilus, Stratophilus, a participant a participant in the inFirst the Council First Council of Nicaea of Nicaea in 325. in At 325. the Atsame the sametime, Christianity time, Christianity in Pitiunt in Pitiunt had beco hadme become widespread widespread much muchearlier earlier than 325, than when 325, whenPitiunt Pitiunt had formed had formed a church a church organization organization headed headed by the by thecity citybishop. bishop. Church Church No. No. 1 has 1 hasrather rather thin thin walls, walls, which which in in combination combination wi withth a a single-nave single-nave structure andand aasignificant significant widthwidth of of 11.3 11.3 m m excludes excludes the the presence presence of of a a stone stone vault vault and and suggests suggests that that the the roof roof of of this this structurestructure was was made made of of rafter rafter (Figure (Figure 13 13).). The The synchronicity synchronicity of of the the temple temple with with the the canaba canaba wallwall is is currently currently debatable, debatable, but but the the dating dating of of the the early early layers layers in in Tower Tower No. No. 1 1 to to the the end end of of thethe 3rd–beginning 3rd–beginning of of the the 4th 4th centuries centuries is is acceptable. acceptable. The The church church did did not not last last long long and and was was destroyeddestroyed by by fire. fire. In In its its place, place, Church Church No. No. 2 2 was was built built in in the the middle middle of of the the 4th 4th century. century. Its Its reconstruction was not done, since for the non-standard asymmetric apse the analogies reconstruction was not done, since for the non-standard asymmetric apse the analogies have not been found yet and this issue requires further study. This church did not last long have not been found yet and this issue requires further study. This church did not last either, and Church No. 3 was built in its place. long either, and Church No. 3 was built in its place.

FigureFigure 13. 13.Reconstruction Reconstruction of of the the appearance appearance of of the the Church Church No. No. 1. 1.

ChurchChurch No. No. 3 3 survived survived better better than than the the previous previous monuments monuments in in the the Pitsunda Pitsunda complex complex andand is is larger larger than than the the two two earlier earlier ones ones (Figure (Figure 14 14).). Unlike Unlike them, them, this this church church can can already already be considered an exemplary basilica building of the Roman-Byzantine style. The division of the inner part of the building, the presence of a faceted apse on the outside, axial and Appl. Sci. 2021, 11, x FOR PEER REVIEW 16 of 18

Appl. Sci. 2021, 11, 4814 16 of 18

be considered an exemplary basilica building of the Roman-Byzantine style. The division of the inner part of the building, the presence of a faceted apse on the outside, axial and longitudinallongitudinal entrances,entrances, asas wellwell asas threethree entrances entrances from from the the narthex, narthex, a a semicircular semicircular altar altar part and alternation of stone rows with brick in the building material testify the influence part and alternation of stone rows with brick in the building material testify the influence of the Hellenistic Roman-Byzantine school of religious architecture [35]. of the Hellenistic Roman-Byzantine school of religious architecture [35].

FigureFigure 14. 14.Reconstruction Reconstruction of of the the appearance appearance of of the the Church Church No. No. 3. 3.

DuringDuring its its reconstruction, reconstruction, we we were were guided guided both both by analogies by analogies with churcheswith churches of the sameof the periodsame period and by descriptionand by description of its probable of its appearance,probable appearance, which was which given bywas I.N. given Tsitsishvili: by I.N. “Tsitsishvili:... one can “… imagine one can the imagine Pitsunda the Basilica Pitsunda in Basilica the form in of the a buildingform of a withbuilding a high with middle a high navemiddle and nave a gable and roof a gable covered roof with covered tiles, lowerwith tiles, side naveslower and side a narthex,naves and with a narthex, lean-to roofs with leaninglean-to againstroofs leaning the main against building. the main The multifaceted building. The apse, multifaceted apparently, apse, had anapparently, independent had pyramidalan independent roof” [pyramidal36]. roof” [36]. AtAt the the end end of of the the 4th–beginning 4th–beginning of of the the 5th 5th century, century, in thein the place place of the of Churchthe Church No. 3,No. the 3, Churchthe Church No. 4No. [37 ]4 was[37] built.was built. Its reconstruction Its reconstruc hastion not has yet not been yet carried been carried out because, out because, firstly, itfirstly, goes beyond it goes thebeyond chronological the chronological framework framework of the reconstructed of the reconstructed model of model the fortress, of the and for- secondly,tress, and similar secondly, to Church similar No. to Church 2, it is distinguished No. 2, it is distinguished by its architectural by its architectural originality, which origi- requiresnality, which additional requires investigation. additional Therefore,investigation. the reconstructionTherefore, the ofreconstruction its appearance of isits the appear- task ofance future is the works. task of future works.

4.4. ConclusionsConclusions TheThe resultsresults presentedpresented areare the the first first large-scale large-scale visualization visualization of of the the appearance appearance of of the the RomanRoman fortressfortress PitiuntPitiunt inin thethe 4th4th centurycentury AD.AD. Obviously,Obviously,with withthe theappearance appearance ofofnew new archaeologicalarchaeological data,data, thethe modelmodel ofof thethe fortress fortress will will be be refined refined and and supplemented. supplemented. At At this this point,point, the the reconstruction reconstruction did did not not pursue pursue a detaileda detailed study study of theof the buildings, buildings, since since there there is no is requiredno required archaeological archaeological material material for doingfor doing so, butso, itbut was it was aimed aimed at visualizing at visualizing the generalthe gen- vieweral view of the of fortress the fortress to convey to convey the historical the histor contextical context in which in which the garrison the garrison of the of fortress the for- andtress the and inhabitants the inhabitants of the easternof the eastern fortification fortification canabas canabas lived. The lived. obtained The obtained results canresults be important in educational and museum work, since the site is in a serious state of disrepair, can be important in educational and museum work, since the site is in a serious state of and the territory is overgrown with rough subtropical vegetation and is abandoned. Even many local residents do not know what overgrown stone wall is located in the very center Appl. Sci. 2021, 11, 4814 17 of 18

of the city of Pitsunda. At the same time, not everyone can get to the territory of the unrecognized republic of Abkhazia and inspect the site for political reasons. Therefore, the use of visualization of this site next to the object via a billboard, and in more detail in the museums of the region using printed materials, video renders of flying around the fortress or immersion in virtual reality (VR), will demonstrate the prominence of this fortress in the historical picture of the Eastern Black Sea coast in the first centuries AD.

Author Contributions: G.T.—management of archaeological exploration and preparation of a publi- cation; A.K.—preparation of drawings; K.G.—processing of 3-D models in programs and preparation of a publication; S.S.—work with archival materials; V.Y.—processing of 3-D models in programs; G.Y.—preparation of material on geological paleoreconstructions. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: The data on the basis of which the study was conducted are presented in the references provided to the article. Conflicts of Interest: The authors declare no conflict of interest.

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