The Croatian-Ottoman wars, 1493 to 1593: from Krbava to Sisak

For a hundred years Croatia lived as a frontier. Peasants plowed with weapons at hand, watchtowers lined the rivers, and the lords of the great noble houses died in battle one generation after another. By the end of the sixteenth century the Croats themselves spoke of what was left of their kingdom as the “remnants of the remnants”. Then, on a June day in 1593, on the banks of the Kupa below the fortress of Sisak, the tide turned.²

Background: a kingdom on the frontier

Since 1102 Croatia had shared its king with Hungary while keeping its own assembly of nobles, the Sabor, and its own viceroy, the ban. When the Ottomans conquered Bosnia in 1463, Croatia found itself on the front line of their advance into Europe, the frontier of Christendom against the expanding sultanate.³

The sides

On one side stood the Croatian nobility, great families such as the Frankapans, Zrinskis and Blagajs with their own retinues, led in war by the ban. Against them stood the Ottoman frontier forces of Bosnia under their sanjak-beys and pashas, with more cavalry and more experienced soldiers, and behind them the full power of the sultan.⁴

From 1527 the Habsburgs took Croatia's side. The defense was paid for largely by the estates of the Austrian lands of Styria, Carinthia and Carniola, and run more and more from Vienna and Graz, so that the frontier became a joint enterprise of the Croatian estates, the dynasty and its German-speaking provinces.⁵

The phases of the war

Raids and Krbava, 1493. In the spring of 1493 an Ottoman force under Jakub Pasha, sanjak-bey of Bosnia, plundered Croatia, Carniola and Styria. On its way home Ban Emerik Derenčin met it on Krbava Field near Udbina in Lika, on 9 September. The ban chose to give battle on the open plain below the castle of Udbina, and the Ottomans destroyed his army. The sources differ on the numbers: the Croatian Encyclopedia makes the two armies equal, while Miljan and Kekez give the Croats more men but the Ottomans more cavalry and more experience.⁶

The losses fell on the ruling class. Many lords of the Frankapan, Zrinski and Blagaj families were killed, and the ban himself was taken prisoner. Yet the Ottomans did not follow up with conquest. For decades they raided rather than occupied, as their main effort went into Hungary, and the county of Krbava itself fell only some thirty years later.⁷

Collapse, 1521 to 1527. The old defensive system broke under Sultan Suleiman the Magnificent. He took Belgrade in 1521, and on 29 August 1526 his army crushed the Hungarian and Croatian host at Mohács. King Louis II died in his flight and left no heir.⁸

The Croatian estates chose their own way. On 1 January 1527, meeting at Cetin, they elected Archduke Ferdinand of Habsburg their king, because they expected his help against the Ottomans.⁹ › Battle of Mohács, 1526

The Military Frontier, 1530s to 1580s. The defense took the form of the Military Frontier, a belt of stone and wooden forts, watchtowers and garrisons along the border. In 1578 the estates of Inner Austria formally took over the defense under Archduke Charles, and a war council in Graz began to direct it; the frontier districts were gradually removed from the authority of the ban and the Sabor. In 1579 the archduke had the fortress of Karlovac built to anchor the Croatian part of the line.¹⁰

The frontier changed the country. Peasant soldiers worked their fields with weapons at hand, ready to drop the plow and fight. New settlers from the Ottoman lands, many of them Orthodox Vlachs and refugees, were given land in return for fighting on their own account, outside the authority of the Croatian lords. Britannica calls this the origin of Croatia's later Serb minority.¹¹

Even so the losses went on, and fortresses fell one after another across the frontier, from Klis near the Adriatic to Čazma in Slavonia, which was lost in 1552.¹²

Szigetvár, 1566. The most famous episode came just over the border, in Hungary. In August 1566 Suleiman besieged the fortress of Szigetvár with a huge army. It was held by Count Nikola Zrinski with a small garrison. In early September, with the fortress lost, Zrinski led the last of his men out in a sortie in which almost all of them died. The sultan himself had died during the siege, on 5 or 6 September.¹³

Turning point: Sisak, 1593

Toward the end of the century Hasan Pasha Predojević, the ambitious governor of Bosnia, set out to take Bihać, Sisak and Zagreb and open the road to the west. In 1591 and 1592 he attacked Sisak, the fortress of the Zagreb cathedral chapter where the Kupa meets the Sava, and both times was driven off. On 15 June 1593 he came back a third time.¹⁴

The garrison, commanded by two canons of Zagreb, Blaž Đurak and Matija Fintić, numbered 300 men by the encyclopedia's count; the Croatian History Museum adds some 500 foreign soldiers. A relief army gathered under Ban Toma Erdődy and the frontier commanders, Andreas Auersperg of Karlovac and Stephan Graswein of the Slavonian frontier, with Ruprecht von Eggenberg in overall command: about 4,500 men in the encyclopedia's count, about 5,000 in the museum's, against an Ottoman army about twice as large.¹⁵

On 22 June the Christian army attacked. Hasan Pasha had crossed the Kupa with part of his army and drawn it up with the river at its back. The Ottoman line gave way before the attack, in which the Karlovac arquebusiers played their part, and with the river behind them the fleeing Ottomans were trapped. Between 7,000 and 8,000 of them drowned in the Kupa, Hasan Pasha among them, while the Christian losses were slight.¹⁶

Aftermath

The Croatian Encyclopedia calls Sisak a turning point: for the first time a military balance was established on the border, the Ottoman conquest of Croatian lands was halted, and the way was opened for the Christian offensives of the Long War, which began that same year and lasted until 1606. The museum's historian, Vlasta Brajković, concludes that at Sisak the Ottoman advance reached its farthest northwestern limit, which was never crossed again.¹⁷

Croatia regained most of its lost lands only after the Ottoman defeat before Vienna in 1683, through the peace treaties of Karlowitz in 1699 and Passarowitz in 1718, and even then much of the reconquered land went to the Military Frontier rather than back to the kingdom.¹⁸

Legacy and memory

The wars left a mark on Croatia's map and people. The Military Frontier, ruled from the war councils rather than by the ban and the Sabor, shrank the land under Croatian control, and the settlers it attracted gave the frontier its mixed Catholic and Orthodox population.¹⁹

They also shaped memory. Miljan and Kekez trace how Krbava became, in chronicles and folk poems from the sixteenth century onward, the first and most disastrous defeat of the Croats, a defeat that shaped everything that followed, and how its story was revived whenever Croatian identity needed strengthening. Sisak became its counterpart, a victory celebrated across Europe in drawings, prints and maps published in Vienna, Augsburg, Nuremberg, Ljubljana and Antwerp, and one that, as the museum put it, ended the century-long defensive begun at Krbava.²⁰ › Battle of Krbava Field, 1493