Fortress of Klis The Klis Fortress ( ) is a medieval fortress situated above a village bearing the same name , near the city of Split , in central Dalmatia , Croatia . From its origin as a small stronghold built by the ancient Illyrian tribe Dalmatae , becoming a royal castle that was the seat of many Croatian kings , to its final development as a large fortress during the Ottoman wars in Europe , Klis Fortress has guarded the frontier , being lost and re - conquered several times throughout its more than two thousand year - long history . Due to its location on a pass that separates the mountains Mosor and Kozjak , the fortress served as a major source of defense in Dalmatia , especially against the Ottoman advance , and has been a key crossroad between the Mediterranean belt and the Balkan rear . Since Prince Mislav of Littoral Croatia made Klis Fortress the seat of his throne in the middle of the 9th century , the fortress has served as the seat of many Croatia ' s rulers . The reign of his successor , Duke Trpimir I , the founder of the Croatian royal House of Trpimirović , is significant for spreading Christianity in the Littoral Croatia . He largely expanded the Klis Fortress , and in Rižinice , in the valley under the fortress , he built a church and the first Benedictine monastery in Croatia . During the reign of the first Croatian king , Tomislav , Klis and Biograd na Moru were his chief residences . In March 1242 at Klis Fortress , Tatars who were a constituent segment of the Mongol army under the leadership of Kadan suffered a major defeat while in pursuit of the Hungarian army led by King Béla IV . After their defeat by Croatian forces , the Mongols retreated , and Béla IV rewarded many Croatian towns and nobles with " substantial riches " . During the Late Middle Ages , the fortress was governed by Croatian nobility , amongst whom Paul I Šubić of Bribir was the most significant . During his reign , the House of Šubić controlled most of modern - day Croatia and Bosnia . Excluding the brief possession by the forces of Bosnian King , Tvrtko I , the fortress remained in Hungaro - Croatian hands for the next several hundred years , until the 16th century . Klis Fortress is probably best known for its defense against the Ottoman invasion of Europe in the early 16th century . Croatian captain Petar Kružić led the defense of the fortress against a Turkish invasion and siege that lasted for more than two and a half decades . During this defense , as Kružić and his soldiers fought without allies against the Turks , the military faction of Uskoks was formed , which later became famous as an elite Croatian militant sect . Ultimately , the defenders were defeated and the fortress was occupied by the Ottomans in 1537 . After more than a century under Ottoman rule , in 1669 , Klis Fortress was besieged and seized by the Republic of Venice , thus moving the border between Christian and Muslim Europe further east and helping to contribute to the decline of the Ottoman Empire . The Venetians restored and enlarged the fortress , but it was taken by the Austrians after Napoleon extinguished the republic itself in 1797 . Today , Klis Fortress contains a museum where visitors to this historic military structure can see an array of arms , armor , and traditional uniforms . Location . The fortress is located above a village bearing the same name , from the Adriatic Sea , on a pass that separates the mountains Mosor and Kozjak , at the altitude of , northeast of Split in Croatia . Owing to its strategic position , the fortress is regarded as one of the region ’ s most important fortification s . Perched on an isolated rocky eminence , inaccessible on three sides , the fortress overlooks Split , the ancient Roman settlement of Salona , Solin , Kaštela and Trogir , and most of the central Dalmatian islands . Historically , the fortress has controlled access to and from Bosnia , Dalmatia and inland Croatia . The importance of such a position was felt by every army that invaded , or held possession of this part of Croatia . Klis Fortress was a point against which their attacks were always directed , and it has been remarkable for the many sieges it withstood . It has been of major strategic value in Croatia throughout history . History . Ancient stronghold of Illyrians and Romans . The ancient Illyrian tribe of Dalmatae , which held a stronghold on this spot , were the first known inhabitants who lived on the site of what is today Klis Fortress . They were defeated several times , and in the year 9 AD , finally annexed by Romans . Today ' s Klis Fortress was known to the Romans by the name of " " Andetrium " " or " " Anderium " " , and in later times " " Clausura " " , which is the origin of later " " Clissa " " and modern " " Klis " " . To the Romans , Klis became famous for its celebrated siege by Augustus , at the time of the Illyrian revolt in Dalmatia . The road that lead from Klis to Salona was called " Via Gabiniana " or " Via Gabinia " , which according to an inscription found at Salona , appears to have been made by Tiberius . Southeast of the fortress , the traces of a Roman camp are still visible , as well as an inscription carved on a rock ; both which are supposed to be contemporary with the siege under Tiberius . The description of this siege during the Illyrian Wars demonstrates that this place was strong and unreachable in those times . Migration period and the arrival of the Croats . After the fall of the Roman Empire , Barbarians plundered the region around Klis . First it was ruled by Odoacer , and then by the Theodoric the Great , after he eliminated Odoacer , and set up an Ostrogothic Kingdom . After Justinian I fought an almost continual war for forty years to recover the old Roman Empire , he seized Dalmatia , and Klis was from 537 , a part of Byzantine Empire . The name of Klis ( " Kleisa " or " Kleisoura " ) was first described in chapter 29 of Emperor Constantine Porphyrogenitus ' " De Administrando Imperio " . While describing the Roman settlement of Salona , Constantine VII speaks of the stronghold , which may have been designed or improved , to prevent attacks on the coastal cities and roads by Slavs . Salona , the capital of the province of Dalmatia was sacked and destroyed in 614 by Avars and Slavs . The population fled to Diocletian ' s walled palace of Split , which was able to hold up . Thereafter , Split rose quickly in importance , as one of Dalmatia ' s major cities . After a few decades , the Avars were driven out by the Croats . This probably happened after 620 , when in second wave Croats migrated on the invitation by the Emperor Heraclius to counter the Avar threat on the Byzantine Empire . Royal Castle . From the early 7th century on , Klis was an important Croat stronghold , and later , one of the seats of many Croatia ' s rulers . In the 9th century , Croatian prince Mislav of Littoral Croatia , from 835 to 845 , made the castle of Klis seat of his throne . Despite Frankish overlordship , the Franks had almost no role in Littoral Croatia in the period from the 820s through 840s . After Mislav ' s death , starting with Duke Trpimir I , Klis was ruled by royal members of the House of Trpimirović , who were at first Dukes of Littoral Croatian Duchy ( " dux Croatorum " ) , and afterwards Kings of the Croatian Kingdom ( " rex Croatorum " ) . They developed the early Roman stronghold into their capital . Relations with the Byzantines greatly improved under the Croatian duke Trpimir I , who moved the dux ' s main residence from Nin to Klis . The reign of Mislav ' s successor Trpimir I , is significant for spreading Christianity in the medieval Croatian state , and for the first mention of the name " " Croats " " in domestic documents . On 4 March , in 852 , Trpimir I issued a " " Charter in Biaći " " ( ) in Latin , confirming Mislav ' s donations to the Archbishopric in Split . In this document Trpimir I named himself ; " " By the mercy of God , Duke of Croats " " ( ) , and his realm as the " " Realm of the Croats " " ( ) . In the same document Trpimir I mentioned Klis as his property — seat . Under Klis , in Rižinice , the duke Trpimir built a church and the first Benedictine monastery in Croatia , which is known from the discovery of a stone fragment on a gable arch from an altar screen , inscribed with the prince ' s name and title . A controversial Saxon theologian of the mid - 9th century , Gottschalk of Orbais , spent some time at Trpimir ' s court between 846 and 848 . His work " " De Trina deitate " " is an important source of information for Trpimir ' s reign . Gottschalk was a witness to the battle between Trpimir and Byzantine strategos , when Trpimir was victorious . During the reign of Croatian king Tomislav , who had no permanent capital , the castle of Klis along with Biograd , were his chief residences . Knights Templar . From the early 12th century , and after the decay of the native Croatian royal family of Trpimirović , the castle of Klis was mainly governed by Croatian nobility , under the supremacy of Hungarian kings . The Kingdom of Croatia and the Kingdom of Hungary were , from 1102 , a personal union of two kingdoms , united under the Hungarian king . Andrew II of Hungary was extremely favorably disposed towards the Templars . During his participation in the Fifth Crusade , he appointed Pontius de Cruce , Master of the Order in the Hungarian Kingdom , as a regent in Croatia and Dalmatia . After his return in 1219 , in recognition of the great logistical and financial support which the Order had given him during the campaign , he granted the Order the estate of Gacka . Even before his departure from the city of Split in 1217 , he had made over to the Templars the castle of Klis ( " Clissa " ) , a strategic point in the hinterland of Split ( " Spalato " ) , which controlled the approaches to the town . The king Andrew was reluctant to entrust the castle of Klis to any of the local magnates , knowing what great harm could come from that castle . It was the king ' s will that Split receive the castle of Klis for the defense of their city . The city of Split showed little interest in the royal favors , so the king entrusted Klis into Templars hands . Shortly after this , the Templars lost Klis , and , in exchange , the king gave them the coastal town of Šibenik ( " Sebenico " ) . Mongol siege . Tatars under the leadership of Kadan experienced a major failure in March 1242 at Klis Fortress , when they were hunting for Béla IV of Hungary . The Tatars believed that the king was in the Klis Fortress , and so they began to attack from all sides , launching arrows and hurling spears . However , the natural defenses of the fortress gave protection , and the Tatars could cause only limited harm . They dismounted from their horses and began to creep up hand over hand to higher ground . But the fortress defenders hurled huge stones at them , and managed to kill a great number . This setback only made the Tatars more ferocious , and they came right up to the great walls and fought hand to hand . They looted the houses and took away much plunder . Upon learning that the king was not there , they abandoned their attack , and ascending their mounts rode off in the direction of Trogir , a number of them turning off toward Split . The Mongols attacked the Dalmatian cities for the next few years but eventually withdrew without major success , as the mountainous terrain and distance were not suitable for their style of warfare . They pursued Béla IV from town to town in Dalmatia . The Croatian nobility and Dalmatian towns such as Trogir and Rab helped Béla IV to escape . After this failure , the Mongols retreated and Béla IV rewarded the Croatian towns and nobility . Only the town of Split did not help Béla IV in his escape . Some historians claim that the mountainous terrain of Croatian Dalmatia was fatal for the Mongols , because they suffered great losses when attacked by the Croats from ambushes in mountain passes . Other historians claim that the death of Ögedei Khan ( ) was the only reason for retreat . Much of Croatia was plundered by the Mongols , but without any major military success . Saint Margaret ( January 27 , 1242 – January 18 , 1271 ) , a daughter of Béla IV and Maria Laskarina , was born in Klis Fortress during the Mongol invasion of Hungary - Croatia . Šubić ' s rule . The weakening of royal authority under Stephen V of Hungary allowed the House of Šubić to regain their former role in Dalmatia . In 1274 , Stjepko Šubić of Bribir died , and Paul I Šubić of Bribir succeeded him as the family elder . Soon , Ladislaus IV of Hungary , recognizing the balance of power in Dalmatia , named Paul I as Ban of Croatia and Dalmatia . Ladislaus IV died in 1290 leaving no sons , and a civil war between rival candidates , pro - Hungarian Andrew III of Hungary , and pro - Croatian Charles Martel of Anjou , started . Charles Martel ' s father Charles II of Naples , awarded all Croatia from Gvozd Mountain ( ) to the river Neretva mouth hereditary to Paul I Šubić of Bribir . Thus , Charles converted Paul ' s personal position as Ban into a hereditary one for the Šubić family . All the other nobles in this region , were to be vassals of Paul Šubić . In response , Andrew III in 1293 issued a similar charter for Paul Šubić . During this struggle over the throne , George I Šubić of Bribir , Ban Paul ' s brother went to Italy , visiting the pope and the Naples court . In August 1300 , George I returned to Split , bringing Charles Robert with him . Paul Šubić accompanied Charles Robert ( later known as Charles I of Hungary ) to Zagreb , where he was recognized as king ; then they proceeded to Esztergom , where , in 1301 , the Archbishop of Esztergom crowned him as King of Hungary and Croatia . Paul I Šubić , Ban of Croatia and Dalmatia , became Lord of all of Bosnia in 1299 . Although supporting the king , Paul I continued to act independently , and ruled over a large portion of modern - day Croatia and Bosnia . He appointed his brothers as commissars of Dalmatian cities , and gave Split to his brother Mladen I Šubić , and Šibenik , Nin , Trogir and Omiš to his brother George I Šubić . After George I Šubić died in 1302 , his brother Mladen I Šubić ruled as a Bosnian Ban over Bosnia from Klis Fortress , until he was killed in a battle during 1304 . Then , Šubić gave the Klis Fortress to his son Mladen II Šubić , who ruled over Bosnia like his uncle Mladen I . George II Šubić and his son , Mladen III Šubić , ruled over Klis Fortress until the late 14th century . During summer - long festivities in Klis Fortress , open to the whole population , Mladen III Šubić gave his sister ' s Jelena Šubić hand in marriage to Vladislaus of Bosnia , from the House of Kotromanić . Jelena Šubić gave birth to the first Bosnian King , Tvrtko I , who later inherited the fortress . Petar Kružić and the Uskoci . Owing to its location , Klis Fortress was an important defensive position during the Ottoman conquest of the Balkans . The fortress stands along the route by which the Ottomans could penetrate the mountain barrier separating the coastal lowlands from around Split , from Turkish - held Bosnia . The Croat feudal lord Petar Kružić gathered together a garrison composed of Croat refugees , who used the base at Klis both to hold the Turks at bay , and to engage in marauding and piracy against coastal shipping . Although nominally accepting the sovereignty of the Habsburg Emperor Ferdinand I , who obtained the Croatian crown in 1527 , Kružić and his freebooting Uskoks were a law unto themselves . When a large Turkish force threatened the fortress , Kružić appealed to Ferdinand I for help , but the Emperor ' s attention was diverted by a Turkish invasion into Slavonia . For more than two and half decades , Captain Kružić , also called " ( Prince of Klis ) " , defended the fortress against the Turkish invasion . Kružić led the defense of Klis , and with his soldiers fought almost alone against the Ottomans , as they hurled army after army against the fortress . No troops would come from the Hungarian king , as they were defeated by the Ottomans at the Battle of Mohács in 1526 , and the Venetians baulked at sending any help . Only the popes were willing to provide some men and money . Final Ottoman siege . Pope Paul III claimed some rights in Klis , and in September , 1536 , there was talk in the Curia of strengthening the defenses of the fortress . The Pope notified Ferdinand that he was willing to share the costs of maintaining a proper garrison in Klis . Ferdinand I did send aid to Klis and was apparently hopeful of holding the fortress , when the Turks again laid siege to it . Ferdinand I recruited men from Trieste and elsewhere in the Habsburg lands , and Pope Paul III sent soldiers from Ancona . There were about 3 , 000 infantry in the reinforcements , which made a sizeable relief force , that were commanded by Petar Kružić , Niccolo dalla Torre , and a papal commissioner Jacomo Dalmoro d ' Arbe . On March 9 , 1537 , they disembarked near Klis , at a place called S . Girolamo , with fourteen pieces of artillery . After Ibrahim ' s death , Suleiman the Magnificent sent 8 , 000 men under the command of Murat - beg Tardić ( Amurat Vaivoda ) , a Croatian renegade who had been born in Šibenik , to go and lay siege to Klis fortress ( " Clissa " ) , and fight against Petar Kružić . An initial encounter of the Christian relief force with the Turks was indecisive , but , on March 12 , they were overwhelmed by the arrival of a great number of Turks . The attempts to relieve the citadel ended in farce . Badly - drilled reinforcements sent by the Habsburgs fled in the fear of Turks , and their attempts to re - board their boats at Solin bay caused many vessels to sink . Niccolo dalla Torre and the papal commissioner managed to escape . Kružić himself – who had left the fortress to make contact with the reinforcements was captured and executed : the sight of his head on a stick was too much for the remaining defenders of Klis , who were now willing to gave up the fortress in return for safe passage north . After Petar Kružić ' s death , and with a lack of water supplies , the Klis defenders finally surrendered to the Ottomans in exchange for their freedom , on March 12 , 1537 . Many of the citizens fled the town , while the Uskoci retreated to the city of Senj , where they continued fighting the Turkish invaders . Sanjak centre of Ottoman Bosnia . During the Ottoman wars in Europe , Klis Fortress was , for a century , an administrative centre or sanjak ( Kilis Sancağı ) of the Bosnia Eyalet . On April 7 , 1596 , Split noblemen Ivan Alberti and Nikola Cindro , along with Uskoci , Poljičani , and Kaštelani irregulars , organized an occupation of Klis . Assisted by dissident elements of the Turkish garrison , they succeeded . Bey Mustafa responded by bringing more than 10 , 000 soldiers under the fortress . General Ivan Lenković , leading 1 , 000 Uskoci , came in relief of the 1 , 500 Klis defenders . During the battle , Ivan Lenković and his men retreated after he was wounded in battle , and the fortress was lost to the Turks , on May 31 . Nevertheless , this temporary relief resounded in Europe and among the local population . From the well - fortified position in the Klis Fortress , the Turks were a constant threat to the Venetians and to the local Croatian population in the surrounding area . In 1647 , after the Turkish success at Novigrad , the Turks were said to have 30 , 000 troops ready to attack Split . The Signoria send off two thousand soldiers with munitions and provisions to the threatened area . Although Split and Zadar were strong fortresses , they were clearly in danger . Venetian domination . In 1420 , the Anjou contender Ladislaus of Naples was defeated and forced to sail away for Naples . Upon his departure he sold his " rights " to Dalmatia to the Venetian Republic for the relatively meager sum of 100 , 000 ducats . However , Klis and Klis Fortress remained parts of the Kingdom of Croatia . From that time , the Venetians were eager to take control over Klis , as the fortress was one of the region ’ s most important strategic points . The Venetians fought for decades before they finally managed to re - take Klis . During the Candian War ( 1645 – 1669 ) , the Venetians in Dalmatia enjoyed the support of the local population , particularly the Morlachs ( Morlacchi ) . Venetian commander Leonardo Foscolo seized several forts , retook Novigrad , temporarily captured the Knin Fortress , and managed to compel the garrison of Klis Fortress to surrender . At the same time , a month - long siege of the Šibenik Fortress by the Ottomans in August and September failed . From 1669 , Klis Fortress was in the possession of the Venetians , and it remained so until the fall of the Venetian state . The Venetians restored and enlarged the fortress during their rule . After another , the seventh war with the Turks from 1714 to 1718 , the Venetians were able to advance up to the present Bosnian / Croatian border , taking in the whole Sinjsko field and Imotski . Thereafter the Turkish menace was laid to rest and Venice had no serious challenge to its authority in Dalmatia , until Napoleon extinguished the republic itself in 1797 . The border between Christian and Muslim Europe had been moved further east , and the fortress lost its main strategic importance . Subsequently , Klis was taken by the Austrians . The last military occupation of Klis Fortress was by Axis powers during World War II . Architecture . Klis Fortress is one of the most valuable surviving examples of defensive architecture in Dalmatia . The fortress is a remarkably comprehensive structure with three long rectangular defensive lines , consisting of three defensive stone walls , which are surrounding a central strongpoint , the " " Položaj maggiore " " at its eastern , highest end . " " Položaj maggiore " " or " " Grand position " " is a mixed Croatian - Italian term , dating from the time when Leonardo Foscolo captured the fortress for the Venetians in 1648 . At that time , a village started to spread below the ramparts . The structures of the fortress are mostly irregular , as they were constructed to suit the natural topography . On the hills around Klis , there are several small towers , built by the Turks to keep the fortress under surveillance . Fortress outskirts . The Klis Fortress rises on a bare cliff divided into two parts . The first , lower part is on the west , out topped by Mount Greben from the north . The second , higher part is on the east , and includes the Tower " Oprah " , whose name most likely refers to a specific part in the defense . In this section which was not topped by any side , was located the flat of the Commander . The only entrance into the fortress is from the western side . On the southwest side of the fortress , and below it was a resort ( part of the modern village of Klis ) called " borgo " or " suburbium " , surrounded by double walls with 100 – 200 towers . A similar but smaller resort ( also part of modern village of Klis ) existed below Mount Greben on a plateau called Megdan . This included lazaretto es and quarantines which were in Turkish times called " nazanama " . There were also many inns for travellers , which were used for isolation during epidemics . Thus , the coastal towns , primarily the town of Split was protected from epidemics that came from Bosnia . Near the fortress , there were several sources of drinking water , and the closest was the " Holy Biblical Magi " whose importance was invaluable during long sieges . Present appearance . The fortress was built into the south face of a rocky mass , and is barely discernable from the distance as a man - made structure . The defensive capabilities of the fortress have been tested through history in many military operations . During the centuries of its use , the structure served various armies and has undergone a number of renovations , to keep up with the development of arms . The original appearance of the fortress is no longer known , due to the structural changes undertaken by Croatian nobility , Turks , Venetians and Austrians . The present day aspect of a mostly stone fortress dates back to the restructuring work carried out by the Venetians in the 17th century . First defensive line . Many buildings of the Klis Fortress which are from 17th through 19th centuries are partially or entirely preserved . The Fortress actually consists of three parts , enclosed by walls with separate entrances . The first main entrance was built by the Austrians in the early 19th century , on the place of an earlier Venetian entrance . Left of the entrance there is a fortification erected by the Venetians in the early 18th century . Also , near the main entrance there is a " position Avanzato " built in 1648 , which was repeatedly renewed afterwards . On the ground floor of the fortification there is a narrow over - vaulted corridor , which is called a Casemate . Second defensive line . The second entrance which was significantly damaged in the siege of 1648 , leads to the former medieval part of the fortress previously ruled by a Croatian nobility . After 1648 , Venetians fully restored the second entrance , but its present appearance was made by the Austrians during the early 19th century . Along the northern wall near the second entrance , there is fortress - tower called " Oprah " , the most important medieval fortification of the western part of the fortress . It was mentioned for the first time in 1355 , but later the Venetians made the lower crown on it . Nearby of the entrance are artillery barracks , built by the Austrians in the first half of the 19th century . In 1931 its upper floor was ruined , so now only the ground floor remains . Third defensive line . The third entrance leads to the former medieval part built in the early Middle Ages . The Venetians renewed it several times after conquest in 1648 , and the last upgrade was in 1763 . Within this part of the fortress there is the side tower , built during the 18th century , and completed in 1763 . Following is a repository of weapons built in the mid - 17th century and old powder magazine from 18th century . " House of Dux " later called governor ’ s residence was rebuilt in the mid - 17th century on the foundations of the oldest buildings from the period of Croatian kings . Austrians repaired this building , and there were placed commandments unity of the fortress and Engineering . On the top point of the fortress there was a " New gunpowder storage " , built in the early 19th century . The oldest remaining building with the dome and minaret , was a former square - shaped Turkish mosque , built after the conquest of Klis in 1537 on the foundations of an earlier Old Croatian Catholic chapel . after occupation in 1648 , the Venetians pulled down the minaret and converted it into a Roman Catholic church , dedicated to St . Vitus ( ) . It is a simple constructed square with the octagonal stone roof . There used to be three Altars , dedicated to St . Vid , Virgin Mary and St . Barbara , but today the church has no inventory . In the church there is a Baroque stone sink from the 17th century , which served as a baptistery , where there is engraved the year of 1658 . West of the church is the bastion of Bembo , the largest artillery position in the third defense line and in the whole fortress . It has wide holes for guns , and was built in the half of 17th century on the site of former Kružić ' s tower , and the defensive positions of Speranza . Present day . The Klis Fortress has been developed as a visitor attraction by the " Kliški uskoci " re - enactment association in Klis with the aid of the conservation department of the Ministry of Culture in Split . Visitors to the historic military structure can see an array of arms , armor , and traditional uniforms in a building which was formerly an Austrian armory . Klis is remembered in a Croatian byword based on the resistance of Klis and the strength of its people : " It is difficult for Klis because it is on the rock and it is difficult for the rock because Klis is on it " . In popular culture . The fortress was used in a 1972 . historical film Eagle in a Cage , portraying Saint Helena . Klis is also being used as a location for filming the HBO series " A Game of Thrones " .