Understanding the Layout of Early Coastal Settlement at Unguja Ukuu, Zanzibar Tom Fitton & Stephanie Wynne-Jones∗

Understanding the layout of early coastal settlement at Unguja Ukuu, Zanzibar Tom Fitton & Stephanie Wynne-Jones∗

New investigations at the coastal settlement 0 km 500 of Unguja Ukuu in Zanzibar have demon- Kenya strated the effectiveness of magnetometry as a survey method. The early occupation of this Swahili port, from the sixth century AD, presents a unique opportunity to Unguja develop our understanding of the growth and Ukuu Tanzania development in settlement and trade along Dar es the East African coast. The geophysical survey Salaam has allowed the size of this important site to be reassessed and an industrial component to be identiﬁed. It also offers an insight into the role that early Islamicisation may have played in helping to establish the settlement as a key N port during the growth of the Indian Ocean trade network. Keywords: Tanzania, Swahili, magnetometry, geophysical survey

Introduction The site of Unguja Ukuu occupies the Makime Peninsula, a sandy spit at the south-western end of the island of Unguja (Figure 1), which is part of the Zanzibar archipelago along with the islands of Tumbatu and Pemba. It has long been recognised as an important trading site dating to the earliest period of coastal settlement in this region and has been subject to successive archaeological projects aimed at exploring its chronology and contacts. Unguja Ukuu, along with many sites of this kind along the eastern coast of Africa, was ﬁrst settled in the sixth to seventh centuries AD, and was connected with networks of Indian Ocean trade from the start. These networks are visible in the archaeology via the record of imported goods and exotic foodstuffs that have been found from the earliest levels. Previous research at Unguja Ukuu has sought to understand the chronology of the settlement and to map connections with particular trading partners over many centuries.

∗ Department of Archaeology, University of York, King’s Manor, York YO1 7EP, UK (Email: stephanie.wynne- [email protected]) © Antiquity Publications Ltd, 2017 antiquity 91 359 (2017): 1268–1284 doi:10.15184/aqy.2017.141 1268 otiueapcueo h eea aoto h ieadpoieafaeoki which in Clark framework & a (Horton provide site and as together the site at Ukuu excavations the excavations Unguja test of test layout limited of previous general and nature understand the survey to the of geophysical understanding picture of a at programme contribute aimed A was settlement. contrast, a by project, Ukuu. Unguja Our of location the and Pemba, and Unguja of islands the showing archipelago, Zanzibar the of Map 1. Figure rbbyhv enbahd otntby hyrvae h xsec fapoal early probable a would previously of vessels than existence waterfront. where the the settlement to harbour revealed larger adjacent they shallow immediately notably, a a mosque Most of bordering beached. existence been and have the waterfront, probably to busy site a point the with results between imagined, interface The the ocean. understanding towards the focused and was survey this particular, In nesadn h aoto al osa eteeta nuaUu,Zanzibar Ukuu, Unguja at settlement coastal early of layout the Understanding 1269 niut ulctosLd 2017 Ltd, Publications Antiquity © 1985 ;Juma 2004 ).

Research Tom Fitton & Stephanie Wynne-Jones Unguja Ukuu

Although evidence for occupation at cave sites on both Unguja and Pemba dates back many thousands of years (Chami 2001, 2009; Sinclair et al. 2006), it is only from the seventh century AD that a record of consistent settlement can be traced in the Zanzibar archipelago. Sites characterised by ‘Tana Tradition’ ceramics are found along the coast of both Zanzibar and Pemba (Horton & Clark 1985; LaViolette & Fleisher 1995). From their earliest iterations, these sites were connected to long-distance maritime trade, with imports including ceramics from the Persian Gulf and India, glass and glass beads. They were also significant manufacturing centres of iron and of shell beads. Inhabitants had a mixed diet that involved some hunting, a heavy emphasis on fish consumption, as well as the keeping of chicken; pearl millet and sorghum were the staple crops (Walshaw 2010, 2015). Architecture in the earliest settlements was entirely of daub and timber. Many sites were substantial even at this early date, covering between 4 and 25ha, and have been described as large villages (Fleisher & LaViolette 2013). At around AD 900, older sites such as Unguja Ukuu were either abandoned or greatly reduced in size, and a new settlement pattern emerged, favouring remote islands or peninsulas (Horton in press). Some of these settlements may have had their origins in the ninth century AD, but from the eleventh century, they took on urban forms based around coral buildings. The period between AD 1100 and 1400 was particularly prosperous on the islands of Zanzibar. Archaeology in the archipelago has revealed a great deal about this history of settlement, including its chronology and links with overseas partners. The sites of Unguja Ukuu (Horton & Clark 1985;Juma2004), Mkokotoni (Horton & Clark 1985) and Tumbatu (Horton & Clark 1985; Horton in press) have all been the subject of detailed archaeological excavations. Elsewhere in the archipelago, excavations have been supplemented by systematic settlement survey that has helped relate sites to a broader landscape (Fleisher 2003, 2010). Nonetheless, we still only partially understand the full layout of these settlements, how they related to the sea and to maritime resources, and how the excavated portions fitted within the overall layout. Previous test-pit excavations at Unguja Ukuu (Horton & Clark 1985;Juma2004) have established the presence of settlement remains stretching more than 300m inland into the peninsula, and deep archaeological sediments extending to within around 20m of the foreshore (Figure 2). These have to some extent been mapped using resistivity survey and coring (Juma 2004), although the results were somewhat inconclusive and thus were used chiefly as a guide to the depth of deposits rather than as a means of understanding site layout. The emergent picture is of a site with rich archaeological deposits indicating occupation from at least the seventh, if not sixth, century AD (Juma 1996). It was involved with Indian Ocean trade from the start, as evidenced by the record of imported beads, glass and ceramics, as well as the presence of exotic plants (Boivin et al. 2014: 558). The more mundane artefacts such as ceramics, and the huge majority of the plant and food remains, position Unguja Ukuu among its contemporaries in the region, with a mixed economy of agriculture, fishing and hunting, and a variety of craft activities. © Antiquity Publications Ltd, 2017

1270 enmd oietf abu ra retbihwehrtest a maritime-oriented was ways site the the whether previously or establish has ocean, or attempt area, the No harbour resources. with (Fleisher a terrestrial identify interface and to settlement’s marine made the around been structured consider was to it us that allow would that iue2 a fpeiu xaain n nepeain fteacaooya nuaUkuu. Unguja at archaeology the of interpretations and excavations previous of Map 2. Figure nadubnzn fUgj ku n otnadCak( Clark and Horton and Ukuu, Unguja of zone urban inland xaain tUgj kuhv o,hwvr xlrdtelyu ntekn fdetail of kind the in layout the explored however, not, have Ukuu Unguja at Excavations tal et nesadn h aoto al osa eteeta nuaUu,Zanzibar Ukuu, Unguja at settlement coastal early of layout the Understanding . 2015 .Jm ( Juma ). 2004 dnie oa-a rhtcueadamsu nthe in mosque a and architecture coral-rag identiﬁed ) 1271 niut ulctosLd 2017 Ltd, Publications Antiquity © 1985 eotdapossible a reported )

Research Tom Fitton & Stephanie Wynne-Jones mosque overlooking the creek to the east. Local reports suggest that a ﬁfteenth-century ‘Arab’ house and a mosque once stood close to the beach of Menai Bay to the west (Horton &Clark1985), but coastal erosion has damaged the house, and recent construction has buried or destroyed the remains of the mosque (Figure 2). It has been assumed that the creek was the principal focus of settlement and harbour activity in the later phases of the site, but the earlier and richer phases remain obscure, understood only through small test excavations.

Methodology The research reported here was intended to explore the broader layout of Unguja Ukuu, in order to provide a context for the knowledge gained through previous test excavations. In particular, we were interested in the way that the site was structured around the demands of ocean-going trade. Research conducted under the auspice of the Entrepôt Project at the University of York (in collaboration with Aarhus University, Denmark) has sought to explore the layout of several early ports of trade in northern Europe, the Mediterranean region, East Africa and India during this period for comparative purposes. Fieldwork was based on magnetic gradiometry, which has proved successful at defining site extent and at locating archaeological features elsewhere on the Swahili coast (Fleisher et al. 2012; Wynne-Jones 2012;Welhamet al. 2014). Magnetometry survey has the potential to recover areas of activity, to pick up on disturbed soils and to pinpoint industrial activity. As survey at Unguja Ukuu had a particular interest in how the site was positioned in relation to port facilities and the ocean, and how that relationship might have changed over time, the area between the town and the ocean was explored, with a view to locating harbour facilities and identifying anchorages. Magnetic gradiometry is based on the systematic, passive detection of ground magnetic field orientation across a survey area. Anomalous differences in magnetic field strength and orientation may be measured as a result of the induced polarisation of ferrous objects such as metals or fired ceramics; by the thermoremanent polarisation of iron oxides in the soil as a result of heating beyond the Curie point; the magnetic enhancement of soils as a result of disturbance and redeposition; and even because of the presence of objects with an unusually low magnetic signature relative to their surrounding environment, such as coral. The technique thus has a wide variety of applications, and in this instance it allowed the extent of the site to be mapped using trace signatures of sub-surface features and key activity areas. Without ground-truthing it can be difficult to determine the cause of magnetic anomalies, as the range and amplitude of such anomalies across a given site are in part related to the quantity of iron oxides in the soil. The shape, amplitude and clustering of anomalies may provide some indication of activity; bipolar anomalies, for example, indicate induced magnetism, but might be the result of either ferrous materials or magnetic thermoremanence. In the case of Unguja Ukuu, we hypothesised that industrial activity such as hearths, kilns and smelting or iron-working might be identifiable by the clustering of induced magnetic anomalies. At the same time, the probable zone of settlement was surveyed in the hope of reconstructing building plans of wattle-and-daub architecture © Antiquity Publications Ltd, 2017

1272 iue3 a hwn h ra AD eetdfrsre.Cretsrcue,ras tnigacaooia un and ruins archaeological standing roads, structures, Current survey. for selected shown. (A–D) also areas are the areas bulldozed showing Map 3. Figure famtldtco osac o oendbi.Lmtdts xaain eeundertaken use were the excavations with test reﬁned Limited during were debris. completed areas modern was for other area search for to fourth results detector the the metal and of a 2014, Survey of January 2013. in October season in another ﬁeldwork of season a (Welham the Mnara or Songo postholes, at as and structures, foundations daub structural burnt of of enhancement thermoremanence magnetic the either through oraeso h iewr eetdfrsre ( survey for selected were site the of areas Four nesadn h aoto al osa eteeta nuaUu,Zanzibar Ukuu, Unguja at settlement coastal early of layout the Understanding 1273 iue3 Figure .Trewr oee during covered were Three ). niut ulctosLd 2017 Ltd, Publications Antiquity © tal et . 2014 ).

Research Tom Fitton & Stephanie Wynne-Jones

Figure 4. Magnetometry results from the survey of area A, showing the location of anomalies, ferrous materials, thermoremanence and the placement of trench 2. in 2014 to ground-truth the anomalies seen via the magnetometry (shown as trench 2, Figure 4, and trench 1, Figure 5). A20× 20m grid was staked out across each area using a Leica Zeno DGPS to locate key grid points, and 2m transect markers were then laid east–west across the edges of those grids using 30m measuring tapes. The grids aided precision in data collection, and allowed us to locate the geophysical data results accurately in the GIS. The survey was conducted using a © Antiquity Publications Ltd, 2017

1274 iue5 antmtyrslsfo h uvyo raB hwn h oaino h oqe eru aeil,tae of traces materials, ferrous mosque, the of location the showing B, 1. trench area of of placement survey the the and farming from ridge-and-furrow results Magnetometry 5. Figure on tlatoc vr or ufc etrswr lne sn h ec GSwhere DGPS reference Leica recorded the a using planned on were readjusted features was Surface avoid hour. system to every order the once In temperatures, least bushes. at thorn high point and the grass in high trees, drift by sensor presented obstacles a frequent at the taken of were readings and 0.125 gradiometer, of ﬁeld resolution magnetic sensor dual Grad-601 Bartington nesadn h aoto al osa eteeta nuaUu,Zanzibar Ukuu, Unguja at settlement coastal early of layout the Understanding × .m hssrtg nbe st ahrhg-eouindt nspite in data high-resolution gather to us enabled strategy This 0.5m. 1275 niut ulctosLd 2017 Ltd, Publications Antiquity ©

Research Tom Fitton & Stephanie Wynne-Jones they might assist with interpreting the results of the survey, or the georectification of images; these were added to the GIS during post-processing. Data from the magnetometer was downloaded using the native Bartington Grad-601 download utility, and imported into ArchaeoFusion, a beta-test program published by CAST (Centre for Advanced Spatial Technologies) for processing. Post-processing of the data was kept to a minimum, and consisted of Zero Mean Traverse, clipping to 3 standard deviations of the mean, and destaggering. Raw and interpolated images were georectified and imported into ArcGIS using DGPS data collected in the field. Magnetic anomalies were traced and numbered, and those that could be attributed to modern features that had been mapped during the survey were filtered. The remaining anomalies were then analysed according to shape, size and form. Distinct anomalies were re-examined in ArchaeoFusion using the raw data to isolate signature patterns of field strength and amplitude in order to identify ferrous metals or thermoremanence. This procedure enabled the predictive modelling of the cause and nature of anomalies and clusters of features. These assessments are outlined and discussed below.

Results Area A The strip of land surveyed in area A stretches north–south from an elevated ridgeline within the assumed zone of settlement, onto a low-lying land ‘bridge’ linking to the peninsula (Figure 4). A naval base has been built over the area in recent years, and a road and parade ground have been cleared by bulldozer, creating a section revealing loam sediments 1–2m thick overlying archaeological materials and degraded daub. The walls of several coral-rag buildings have also been exposed or destroyed by the creation of this road. The depth of overburden masks the magnetic signature of buried archaeological materials in much of this zone, but in the areas cleared by bulldozers, we identified a number of particularly distinct anomalies. Ceramics of the Early Tana Tradition (Fleisher & Wynne-Jones 2011)and imported Turquoise-Glazed ceramics recovered from the surface and from the bulldozed regions of area A indicate occupation spanning the seventh to tenth centuries AD. Sweeping the area with a metal detector allowed us to exclude significant contamination from modern debris. It also identified a small number of metal archaeological artefacts close to the surface, including fragments of lead fishing weights, copper wire, a copper-alloy tubular container and a possible flask cap. Around the parade ground we recorded a series of intense bipolar, amorphous magnetic anomalies in an area of general magnetic disturbance, and a small number of weaker linear anomalies (Figure 4). These anomalies are in the vicinity of the previously estimated southern edge of the settlement, an area that Horton and Clark have described as a midden, where their test-pit UU1 revealed large quantities of iron slag and possible haematite ore (Horton & Clark 1985; Horton in press). The broad region of magnetic disturbance indicates a collection or spread of ferrous material, and through its remarkable similarity in shape to those mapped in 1984, it seems likely to represent the middens recorded by Clark and Horton. The larger bipolar anomalies may represent either large ferrous artefacts © Antiquity Publications Ltd, 2017

1276 la hte trpeet oeno rhelgclwse uvyo h oehr was foreshore the not of is Survey it waste. and surface, archaeological the or on result modern debris the represents with probably correlate it is not whether anomaly does magnetic clear but local The materials, undiagnostic erosion. where ferrous from tidal mixed magnetic distance by of mixed short the exposed of a on being beach, area beach are this an the of ceramics indicate behind part pool gradiometry upper tidal magnetic the occasional across the an material of as results act The to side. appears results seaward the which in slope, disturbances the linear the of as down base side clearly running eastern up visible the show still On these are and ( west. ploughing mangroves, and the modern east to of the slope remains steep to extensive widening the while ridge, kilometre, the a of about for south the ftera ed st eiv htti ako antcaoaisi o u oa absence an deposits. to soil due overlying not deep is of anomalies effect magnetic masking of the lack to this but that activity believe archaeological to of us ( leads Juma road by the nineteenth-century of described the site to related the possibly of and waste base, presumably occupation furrow, road, naval and the the ridge of lining agricultural construction clearly and pieces the pits, only pre-dating coral rubbish the in as ground, activity such higher burning this features recent On metal, modern ground. to sloping relate to anomalies rises clearance identifiable the of edge the at more the bulldozer. a or of negative remains front and in structural earth positive archaeological of parallel banking either the prosaic represent as could excavation, without signatures explain magnetic to in difficult by of mapped are middens possibility overlapping spread anomalies large the the The and and indicate intact. anomaly surprisingly anomalies exposed are 2013 bipolar contexts remains the archaeological the of represent that shape suggests unknown may in 1984 an similarity results the that material but gradiometry magnetic damage, bulldozing, induced the of extensive area broad the in The preserved. with highlighted still even is remains probable, stratified of seems quantity now earlier it an indicates bulldozing, presence its but test-pit the midden, of shell site. size this the restricted of of the use base and midden the constraints upper to Time the excavation midden. separating local prevented context, shell remains, barren dense daub almost a possible an from deposits, was deposits this clay excavated Beneath by previously ash. area. characterised deposits and small was midden ceramics and this the Horton, of to and limits corresponds Clark the by probably within phase even later recognisable surface. upper, the were The beneath activity survive of still phases deposits archaeological distinct Two of 0.9m least at that demonstrating raA ttenroetpito h aiePnnua n sprastems exciting most of the south perhaps the is to and located Peninsula, is Makime it the settlement; of ( main point surveyed the narrowest area of the location at the A, be area to presumed is B Area B Area 0.5 pit test A areas. thermoremanent of group overlapping an ( or 0.5m objects metal as such iue5 Figure ot fti ein h rudhsntbe oie yrcn atwrs n bank a and earthworks, recent by modified been not has ground the region, this of North the by destroyed entirely been had Ukuu Unguja of part this that concerns Despite iue4 Figure .Eoino uryn ntewsensd fterdehscetdatog tthe at trough a created has ridge the of side western the on quarrying or Erosion ). nesadn h aoto al osa eteeta nuaUu,Zanzibar Ukuu, Unguja at settlement coastal early of layout the Understanding iue5 Figure rnh2 a xaae nteeg foeo hs ioa anomalies, bipolar these of one of edge the on excavated was 2) trench , .Fo h arw‘ek,tepnnuarssi te igln to ridgeline steep a in rises peninsula the ‘neck’, narrow the From ). 2004 1277 nsitu in .Tesrtgah eeldb h cutting the by revealed stratigraphy The ). hroeaetmtra.Telinear The material. thermoremanent niut ulctosLd 2017 Ltd, Publications Antiquity © ×

Research Tom Fitton & Stephanie Wynne-Jones

Figure 6. Excavation plan of the trench spanning the eastern wall of the mosque. Contexts (005) and (007) are lines of coral debris. hampered by incoming tides, but faint anomalies indicate that further work in this region may be useful, if only to establish the archaeological, modern or geological origins of these features. The most interesting feature lies under the break of slope at the top of the beach, at the northern edge of area B. Here we have identiﬁed a distinct rectangular structure, approximately 18 × 13m on an alignment of 328˚ (Figure 6). This may represent the © Antiquity Publications Ltd, 2017

1278 raC otews ftemi ie oesardebhn h ec fMniByada and Bay Menai of beach the behind ridge a covers ( site, beyond main land low-lying the of of area west small the to C, Area C Area degree acceptable an within falls (Horton structure period the relevant of the orientation for the error as of mosque, a of remains rts hlig,oeo hc a dnial sa13sGog su.I em hta that seems century. It twentieth issue. mid to V early George the 1930s in four a here including erected as area, was identifiable shelter the was or in which structure found the of in also one upright were buried shillings, concrete coins British degraded the twentieth-century and investigate posts early to iron activity, Several excavations thick ancient of shallow ground. series to daub detector; a relate fired metal revealed to did partially the that seem with the few those anomalies result despite as no the inland, gave of intense extend generally Some remains as not and area. the not do that anomalies are be in the signatures recovered might and fragments The which A, activity. ridge, area industrial in the or found of structures side daub Tumbatu burnt beach-facing or of southern, Kisiwani the Kilwa on as anomalies such sites Fleisher in & at similar (Wynne-Jones but AD minted millennium inscription coins second illegible African early an the East We with during centuries. to ridgeline, nineteenth shape the with and and from thirteenth along size coin to fragments, single eleventh daub a the semi-fired recovered to of also belong to number appear large that a ceramics returned survey pedestrian and ( Juma by reported orientation— blocks whose building 330 fragments the roughly coral) as magnetometry—was (finger large Porites the of by lines indicated two as by caused was anomaly n usd h iiso h eteetetmtdb lr n otnbsdo middens on Clark based & Horton (Horton and 1984 Clark in by excavated estimated partially settlement and the identified of limits the outside and ( mosque of style ( Juma by discovered house al aaTaiincrmc aei otesvnht et etre AD. centuries Diagnostic tenth structure. to this seventh of the area to it interior date the lowest ceramics delineated the Tradition Tana At floor structure. Early sandy dense coral a robbed-out a the and with to postholes but associated next levels, unclear, exist house, to was wattle-and-daub used two artefacts, contemporaneous the of roughly concentration between a interface that The seems debris. it coral the to, adjacent similar immediately 900. be and may 750 contexts AD coral between contexts, the Ib, these from period Juma’s with glass from associated of finds fragments finds to but few potsherds, hypothesis were a diagnostic There blocks, no robbed-out sections. and larger, excavated of the wall a by of supported remains the represent may but diameter, laid we this, test to order In aisle. ( on interior an feature the or linear from wall parallel anomaly double a a but 1 as beach, a interpreted the out was facing side side the eastern along the erosion indicate to appear rdoer eut rmae eeldacutro ioa n iermagnetic linear and bipolar of cluster a revealed C area from results Gradiometry xaainas eoee vdneo ateaddu rhtcueblw and below, architecture wattle-and-daub of evidence recovered also Excavation side western its on traces of faintness The beach. the above just located is anomaly The × mtec ( trench 4m nesadn h aoto al osa eteeta nuaUu,Zanzibar Ukuu, Unguja at settlement coastal early of layout the Understanding otni press in Horton iue5 Figure 2004 iue6 Figure rnh1 unn atws costeesenwl fthe of wall eastern the across east–west running 1) trench , ,wihHro a gi ugse a ersn new a represent may suggested again has Horton which ), .Teaoayrpre eei otesuho raA, area of south the to is here reported anomaly The ). .Ecvto eeldta h obelna magnetic linear double the that revealed Excavation ). iue7 Figure 1991 1279 .Ti rai urnl eoe ocultivation, to devoted currently is area This ). ,admthsteaineto h ntM unit the of alignment the matches and ), 2004 ,fligbten2 n 0m in 100mm and 20 between falling ), ˚ h oie rget r o as not are fragments Porites The . 1985 niut ulctosLd 2017 Ltd, Publications Antiquity © ). 2012 ).

Research Tom Fitton & Stephanie Wynne-Jones

Figure 7. Magnetometry results from the survey of areas C and D, showing the location of anomalies, iron posts, iron and copper artefacts and areas of thermoremanence.

Area D This location to the west of area C was surveyed in order to give context to the find of a Swahili coin (Figure 7). Magnetic gradiometry revealed faint traces indicative of coral structures in the ploughed field where the coin was found, and two clear linear features under the roadway beyond the field. The latter features were partially visible on the © Antiquity Publications Ltd, 2017

1280 oa,wihfre ierfaueo naineto 330 of alignment craft an on and feature the linear life to a daily formed related which understand was coral, we it ports. while that Swahili even early ways in site, the intertwined the been of of suggests have some settlement to life the activity confirms daily of the position This assumed to zone. the central activity. to maritime was close midden, so industry as is well this ( this Horton as that that by fact industrial, area The of this zone. site in this 15– recorded a in around slag was A, and area this ore in that iron anomalies The suggests dipolar creek, of the identification information from The our to Ukuu. 20m significantly Unguja add of survey site geophysical the of on season pilot this from results The the of Discussion area this that AD. No centuries suggest fifteenth coins artefacts. to the non-ferrous thirteenth but other the location, to of this dates number site at small found a mirror, were a and ceramics possibly coins; disc, diagnostic bronze four flat script; a Further of decorative ground. the fragment with the walls; a on included buried visible finds of that metal-detected remains and than the surface extent probably greater a are demonstrate They results rubble. magnetometry coral as identifiable and surface h hl otadissronigmrtm otx.I localne h urn theory between current relationship the the challenges also extension, It by context. maritime and, surrounding interpretation waterfront its our and alters public and This port the creek. whole sailors open tidal the of the of the orientation faced of use have shelter the to the the seem of than for waterfront rather this Bay, perhaps Menai on mosque, of facilities mainland Port water a site. the settlement the including the from at of waterfront arriving limits Ukuu to merchants the busy Unguja adjacent extends a therefore early area B encompass of area the from to extension that into evidence be noting The southern settlement peninsula. will worth a the the is interior onto perhaps of it the and however, extension stage, ocean, of possible this the the excavation At indicates function. Further and discovery dating. date its for its later confirm submitted to was be necessary which will mosque, and the structure, of phase earliest the represents but structure mosque timber the of The phase earliest 3) the with structure. unrelated contemporaneous an was of structure part timber is three and The far, mosque so the 2) pre-dates excavated structure area timber small The the 1) of basis forward: the of put phase on be coral but can the unclear, hypotheses and presently structure AD is seventh–tenth-centuries timber the this mosque in between the period relationship early The an occupation. to of date AD. phase to adjacent centuries appears structure fourteenth which wattle-and-daub mosque, or to timber this thirteenth the unknown to the previously indicates a in identified coral occurred ceramics also have imported the have We of may of fragments robbing small fragmentation this and structure, that The this suggest from mosque. blocks a coral larger of of robbing presence former the indicate nae ,w dnie tutrlrmiscmrsn infiatqatt fPorites of quantity significant a comprising remains structural identified we B, area In hrolsmlshv enotie rmvroscnet nteecvto fthis of excavation the in contexts various from obtained been have samples Charcoal eeeoe sacrlbuilding. coral a as redeveloped unrelated. physically was nesadn h aoto al osa eteeta nuaUu,Zanzibar Ukuu, Unguja at settlement coastal early of layout the Understanding 1281 npress in ˚ h aeil n alignment and materials The . niut ulctosLd 2017 Ltd, Publications Antiquity © a niaeiron-working indicate may )

Research Tom Fitton & Stephanie Wynne-Jones that early mosques were centrally situated within urban zones in Swahili towns, and might point to multiple processes of Islamicisation in different regions of East Africa (cf. Horton 1991). In area C we were able to rule out present-day debris and interference as the cause of the magnetic anomaly identified in 2013, but the recovery of several British coins from the 1930s, and the discovery of concrete and metal posts near the shoreline, indicates that it is probably related to twentieth-century activity. It is possible, however, that these remains are unrelated and that an earlier phase of activity is still preserved in this area. The discovery of early Swahili coinage in area D, along with various other metal artefacts and several coral-rag walls, indicates that this was occupied around the fourteenth to fifteenth centuries AD. It seems that the settlement at Unguja Ukuu may have shifted over time, or have been redeveloped on several occasions, although the nature of these moves, along with their purpose or consequence, is as yet unclear. Further work is necessary to investigate the size of the settlement in this period, especially as the picture is complicated by recent building and earthworks on the site, which make surface observations more difficult. Collectively, these results indicate that during the early occupation of Unguja Ukuu, between the seventh and tenth centuries AD, the town occupied a prominent coastal location with maritime access from the sea via Menai Bay, and with exploitation of the various resources of the mangrove creek east of the peninsula. In this scenario, the newly identified mosque found in area B probably marked the limit of the harbour, as seen at other Swahili coastal towns in later periods (Fleisher et al. 2015). It may have had a counterpoint farther west along the beach in the form of another mosque. As well as demonstrating the presence of a local Islamic community at this date, the harbour-edge mosques would have served as beacons to passing or incoming maritime traffic. There is a contrast between the position of this mosque, on the edge of the settlement near the ocean, and the central mosque of similar date at Shanga, a site on the north Kenya coast that has been the type-site by which urban Islam has been understood for this region. At Shanga, a model has been suggested by which the mosque occupied a central space with access controlled by different social groups (Horton 1991). Islam was therefore at the heart of the settlement (spatially and figuratively) from the start. At Unguja Ukuu, a mosque on the edge of the site, facing the ocean, might suggest a somewhat different role, with the outward-facing aspect of the mosque being prioritised. This suggests more diversity in the route to Islamicisation than has previously been recognised. The industrial zone in area A was probably related to the working of the harbour. Furthermore, the location of the mosque ‘beyond’ this area relative to the known occupation zone creates a larger site boundary that includes this harbour/industry area, positioning it within the orbit of the settlement rather than on the edge. It may be that in addition to the usual necessities of boat building and repair, and fishing and trade, industry formed a key component of harbour activity at Unguja Ukuu. The successful identification of so many previously unknown archaeological features demonstrates the potential both for further work at Unguja Ukuu, and for geophysical survey in East Africa in general. We have been able to extend the known limits of Unguja Ukuu, re-orient the site in relation to its harbour facilities and raise questions about the relationship between public and working spaces in early Swahili society. © Antiquity Publications Ltd, 2017

1282 − Fleisher − Chami Boivin Fleisher Fleisher Fleisher Fleisher fAcaooyadAcetHsoy psl nvriy h sacr ru ebro h DNRF-funded the of References member group core a (DNRF199). University is Aarhus She Evolutions, University. Network the Urban Uppsala for to History, Centre due Ancient by also and funded currently are Archaeology is Wynne-Jones Stephanie of Thanks ﬁeld. Søren the Bogucki. in Fitton, Elizabeth time Tom and Aude and equipment Wynne-Jones, a Sapere of Bogucki loan Stephanie Research the Mateusz for Independent by York Croix, of for University conducted Sarah Council was Hawkes, support. Danish Fieldwork their Jason the for Sindbæk). Sindbæk, of Antiquities, We Project Søren of Zanzibar. 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Research Tom Fitton & Stephanie Wynne-Jones

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Received: 15 January 2016; Accepted: 26 August 2016; Revised: 1 February 2017

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