THE FORTRESS OF GRADISCA D’ISONZO The Isonzo and the Karst region have always been a natural boundary, where the Friuli plain ends to the east. In the territory around Gradisca, the presence of some important rock outcrops of karst origin on the terraces formed over thousands of years from the Isonzo, in time offered the ideal settlement for forts. It is conceivable that there is a fortress which was lost as a result of the constructions that overlapped it over time. Access from the east took place, and still takes place through the so-called "threshold of Gorizia", a strip of land between the mountains that leads one from Ajdovščina to the capital of the Isontino and past the Isonzo, to the Friuli plain and thus towards the Italian peninsula. It has always been a strategic place, and for this reason, it has always been contended. In 181 A.C. Rome began the colonization of these lands by sending 3000 families to implement the land division of the Friuli plain and the construction of Aquileia. After the first inevitable clashes, the Romans finally found an agreement with the indigenous peoples occupying the plains and left the mountain areas to the Celts or Carni. The land was thus reclaimed through this land division and houses for the settlers were built. In some cases, the first villages would have been formed around these settlements, water put into regime, and roads built, one of which, the Gemina, started from Aquileia and led to Emona (Ljubljana). As on all Roman roads, refreshment stations arose along this road, like on today's highways, and at the eleventh mile it is assumed that the MUTATIO AD UNDECIMUM was built: A refreshment station with an interchange for horses, tavern and market, situated a few miles before the PONS SONTI, the bridge on the Isonzo that once stood at the Mainizza. Archeological finds were discovered in the 20s and in 1936 in countryside around Gradisca. It was not much, but enough to speculate with reliable certainty that MUTATIO was situated on the Mercaduzzo. What followed next was the fall of the Roman Empire, the barbarian invasions, the arrival of the Lombards, devastation, reconstruction and repopulation. The oldest written document regarding the history of Gradisca is the diploma of April 29, 967 with which the Emperor Otto I assigned the entire territory between the Isonzo and the Livenza river to the church of Aquileia. Other mentions of the name Gradisca date back to 1031 in the act of consecration of the renewed Basilica of Aquileia made by Patriarch Poppone and, then, with the confirmation of the assets for the Chapter of Aquileia made on July 20, 1176 by the Emperor Frederick Barbarossa. 1 Through a leap in time we find ourselves in the thirteenth century, when the Counts of Gorizia obtained rights over territories belonging to the Patriarchate of Aquileia, and specifically the Isonzo plain. Even amid countless episodes of conflict, the church of Aquileia tolerated the presence of the Counts of Gorizia on their land, but in 1420 this delicate balance was broken by the arrival of the Venetians in Friuli, which put an end to the secular patriarchy and the Isontino once again found itself at the center of territorial conflicts. After an initial, difficult coexistence between the Count of Gorizia and the Republic of Venice, the latter decisively claimed the possession of the territories formerly belonging to the Patriarchate of Aquileia. Clashes inevitably followed, but Venice at that time was a real superpower and the Count of Gorizia renounced all claims. To add to the difficulties were the first Turkish raids on our territory between 1470 and 1472. In 1473 Venice decided to build a defensive line on the right bank of the Isonzo, from Bovec to the sea, and through the Citizen of Frattina project, a pile driven rampart was built and punctuated by the presence of forts or "Bastids" with garrisons ready to intervene in the localities of Mainizza, Farra, Gradisca, Fogliano and Villesse. The people of Friuli were taxed for the implementation of the defense works, however, on October 29, 1477 the Turks, who were probably helped by the Count of Gorizia, crossed the bridge on the Isonzo at Piuma and bypassed the Venetian defenses; at the Groina valley they drew attention from the Gradisca garrison that fell in the ambush once it arrived and was defeated. They perished nearly all the cavalry in battle including the commander Jerome Novello Allegri and his son. At this point the Venetian Senate decided to build a proper fortress on the Isonzo, taking advantage of the existing "Bastida" of Gradisca, built at the outcropping spurs of karstic rock. In order to provide safe construction, the Serenissima signed a twenty-year agreement of non-belligerence with the Turks in January 1479, which was solemnly proclaimed in Piazza San Marco on April 25 of that year, and which handed over the Albanian city of Shkodra after suffering two sieges in a brief period of time, and appointed four providers, Domenico Giorgio, Candiano Bollani, Zaccaria Barbaro and Giovanni Emo to trigger the construction of the fortress of Gradisca. They allocated right from the start of the project the military engineers Enrico Laufer from France and Giovanni Borrella, who initially designed a menagerie for 2400 horses between Gradisca and Fogliano, and in 1483 built a fortress on Mercaduzzo to defend the workers who worked in the construction of the fortress whose project, later , was carried out by Enrico Gallo and Giacomo Contrin, of which the latter was the designer of the Orzinuovi fortress in Brescia (1477), one of the most experienced military engineers the Serenissima possessed. 2 The oldest image of Gradisca (from M. Sanudo, “Itinerario per la terraferma veneziana”, 1483) The construction of this outpost, which functioned as a bulwark towards the east in defense of Turkish raids, also probably had the dual function of contraposition to the Count of Gorizia and later to the Empire. The stone preserved in the city lapidary contains the following text: GRADISCAM VICULI APPELATIONE TURCORUM INCURSIONIBUS OPPOSITAM CONDIDERE VENETI – Named after the village the Venetians founded Gradisca against the Turkish raids. The fortress of Gradisca is an example of military architecture that we can place between the so-called "transition fortresses" which arose in the late fifteenth and early sixteenth century, in an era of transformation that saw the transition from the late medieval fortifications , at which time firearms were just beginning to be enforced, to the “modern” fortifications introduced by Giuliano da Sangallo and Francesco di Giorgio Martini, who satisfied the conditions required by the evolution of artillery. In fact, the outer wall built by the Republic of Venice between 1479 and 1499 is characterized by circular towers, connected by thick walls, while the walls of the castle, built later on, encase the bulwarks within a polygonal form to protect inner building structures. Until the end of '500, military defense occurred through the only defenses consisting of high and mighty walls and moats and barriers close to the gates, the medieval ramparts included towers and walkways, equipped with slits for the crossfire which was carried out using the bow and crossbows. There were however "dead" corners, i.e. unprotected areas. The walls were suitable to defend themselves from the arrows and catapults (which had a maximum range of 200 m), but ineffective in counteracting against firearms, especially by the artillery, implemented from '500. With a modern bastion fortification, equipped with a 3 support shoe, planimetric angular forms were studied, that eliminated the unprotected angles. The fortress of Gradisca had a perimeter of 1800 ml, was pentagonal shaped with an irregular pattern to accommodate the rocky outcrops, surrounded by a moat 17 Venetian steps wide, about 30 m, partially powered by the Isonzo and the Roggia canal, the walls, about 22 m high and with a thickness varying between 3 and 4 m, shared seven towers (Torrione della Campana, Torrione di San Giorgio, Torrione del Portello, Torrione della Spiritata, Torrione della Marcella, Torrione della Calcina e Torrione del Palazzo) and two gates. A third one, named "rescue gate", was built later, during the Archduke's time to be used as an escape route directly on the river or for the provision of supplies during sieges. The Fortress of Gradisca and San Salvatore – Drawing (Correr Museum, Venice) 4 The Western Gate or Gate of Trieste, later the Port of Italy, was directed precisely towards the west, while the Old Port, also called the Farra Gate or Gate of Germany, faced north, was later eliminated and incorporated in the tower St. George; This new arrangement caused the change of the road axis via Lunga that was moved towards the Porta Nuova. Indeed, tracing a straight line along today’s Via Battisti on the height of the Loggia dei Mercanti, it ends in the tower of St. George inside which the original gate can be found sealed. An inclined ramp made from backfill was built over the edge of the moat along the whole perimeter, and razed up to the portion of the belt course or string course. This allowed the artillery to strike the area of interest. The importance of these fortifications is underlined by the presence in all the maps of the time, which are the only reference to document their existence after their leveling to open new spaces to the city. Equipped with dry ditch and counterscarp walls, the ramparts had an irregular shape in relation to the lack of symmetry of the walls. The western ones were quite similar the characteristic design of this type of defense, the rampart of the north side was instead composed of two parts and crossed by the access road which was thus directly controlled.