Siege of Klis The Siege of Klis or Battle of Klis ( , ) was a siege of Klis Fortress in the Kingdom of Croatia within Habsburg Monarchy . The siege of the fortress , which lasted for more than two decades , and the final battle near Klis in 1537 , were fought as a part of the Ottoman – Habsburg wars between the defending Croatian - Habsburg forces under the leadership of Croatian feudal lord Petar Kružić , and the attacking Ottoman army under the leadership of the Ottoman general Murat - beg Tardić . After decisive Ottoman victory at the Battle of Krbava field in 1493 , and especially after the Battle of Mohács in 1526 , the Croats continued defending themselves against the Ottoman attacks . The Ottoman conquest during the early years of the 16th century prompted the formation of the Uskoks , which were led by Croatian captain Petar Kružić , also called " ( Prince of Klis ) " . As a part of the Habsburg defensive system , Uskoks used the base at Klis as an important defensive position . They fought almost alone against the Ottomans , and for more than two decades defended the fortress against the Ottoman attacks . After the final battle , which resulted in an Ottoman victory and in Petar Kružić ' s death , the Klis defenders , who were lacking in water supplies , finally surrendered to the Ottomans in exchange for their freedom on March 12 , 1537 . Citizens fled the town , while the Uskoci retreated to the city of Senj , where they continued fighting the Ottoman army . Klis became an administrative centre or sanjak ( Kilis Sancağı ) of the Bosnia Eyalet , and would remain so for a century . Background . After the fall of the Kingdom of Bosnia into the Ottoman hands in 1463 , the southern and central parts of the Kingdom of Croatia remained unprotected , the defense of which was left to Croatian gentry who kept smaller troops in the fortified border areas at their own expense . Decisive Ottoman victory at the Battle of Krbava field in 1493 , shook all of Croatia . However , it did not dissuade the Croats from making more decisive and persistent attempts at defending themselves against the attacks of the much larger enemy . A new wave of Ottoman conquest began in 1521 , after which a good portion of Croatia was conquered or pillaged . On August 29 , 1526 , at the Battle of Mohács , the Christian forces led by King Louis II were defeated by Ottoman forces led by Sultan Suleiman the Magnificent . Louis was killed in the battle , which resulted in the end of the independent Kingdom of Hungary as he died without an heir . Both the Kingdoms of Hungary and Croatia became disputed territories with claims from both the Habsburg and Ottoman empires . Habsburg Emperor Ferdinand I , who was a brother of Holy Roman Emperor Charles V , married the sister of Louis II and was elected King by the nobles of both Hungary and Croatia . 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 Ottoman - 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 Ottomans at bay , and to engage in marauding and piracy against coastal shipping . Although nominally accepting the sovereignty of the Habsburg Emperor Ferdinand , who obtained the Croatian crown in 1527 , Kružić and his freebooting Uskoks were a law unto themselves . Siege . Failed attempts . From 1513 , Petar Kružić was one of the commanding officers of Klis Fortress . The Ottomans attempted to conquer the Klis Fortress on several occasions . The first major attempt was by Skender - beg Ornosović in 1515 . The Ottomans captured Klis , a village just below the fortress bearing the same name , but the garrison in the fortress above held . Kružić was promoted to captain of the Klis Fortress by the ban Petar Berislavić in 1520 . The second major attempt was in 1520 , and a year later another attempt was made by Makut - paša , with additional 2 , 000 infantry , 50 horsemen and siege equipment . Another unsuccessful attempt was made in 1522 , by Hasan - paša from Mostar and Mehmed - beg Mihalbegović . Later that year , Mihalbegović made another attempt at a siege with 3 , 000 men , but failed again . During 1523 , Klis Fortress was again under attack by the Sultan ' s army . Attempts were also made by Gazi Husrev - beg in 1526 and 1528 , and later in 1531 and 1532 . In 1534 , the Ottomans under Mihalbegović laid a months - long siege with a constant concentrated cannonade to the fortress . Ferdinand urged the Pope to send ships to relieve the Ottoman siege . Although the Ottomans eventually lifted the siege , Ferdinand was displeased that the Pope had provided no assistance in the defense of the fortress . In 1535 , the Ottomans tried to seize the fortress by treachery , and again in 1536 , but they failed on both occasions . During that year the Ottomans started a new siege which would last until the final fall of the fortress . When a large Ottoman force threatened the fortress , Kružić appealed to Ferdinand for help , but the Emperor ' s attention was diverted by an Ottoman attack in Slavonia . Kružić led the defense of Klis , and with his soldiers fought almost alone against the Ottomans , as they repeatedly hurled armies against the fortress . No troops from the Hungarian king arrived , as they were slaughtered by the Ottomans at the Battle of Mohács in 1526 , and the Venetians baulked at sending any help . Only the pope was willing to provide some men and money . Final battle . 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 did send aid to Klis and was apparently hopeful of holding the fortress , when the Ottomans again laid siege to it . Ferdinand recruited men from Trieste and elsewhere in the Habsburg lands , and the Pope 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 sent 8 , 000 men under the command of Murat - beg Tardić ( Amurat Vaivoda ) , a Croatian who had been born in Šibenik , to go and lay siege to Klis fortress ( " Clissa " ) , and fight against Kružić . An initial encounter of the Christian relief force with the Ottomans was indecisive , but , on March 12 , they were overwhelmed by the arrival of a great number of Ottomans . The attempts to relieve the citadel ended in farce . Badly - drilled reinforcements sent by the Habsburgs fled in fear of the Ottomans , 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 overwhelmed the remaining defenders of Klis , who were now willing to give up the fortress in return for safe passage north . After 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 Ottoman army . Aftermath . During the Ottoman wars in Europe , Klis Fortress became an administrative centre or sanjak ( Kilis Sancağı ) of the Bosnia Eyalet , and would remain so for a century . As the first Sanjak - Beg of Klis , Murat - beg Tardić built a notable mosque inside the Klis Fortress . That same year , the Ottoman forces took Vrana , while Nadin and Perušić fell in 1538 . Months after the fall of Klis , the Ottoman – Venetian War of 1537 - 1540 started , and in that war , as well as the Ottoman – Venetian War of 1570 - 1573 , the Ottomans took much of the Dalmatian hinterland near Šibenik and Zadar . On April 7 , 1596 , Split noblemen Ivan Alberti and Nikola Cindro , along with Uskoci , Poljičani , and Kaštelani irregulars , organized a liberation of Klis . Assisted by dissident elements of the Ottoman 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 Ottomans , on May 31 . Nevertheless , this temporary relief resounded in Europe and among the local population . The Venetians fought for decades before they finally managed to re - take Klis . During the Cretan War of 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 .