Hundred Years' Croatian–Ottoman War

The treaty of Constantinople had satisfied neither John Szapolyai nor Austrian Archduke Ferdinand, whose armies begin to skirmish along the borders.

A charter dated September 20, 1537, titles Pavle Bakic as Despot and called all Serbs to join Bakić as the Serbian Despot.

Attempts made by King Ferdinand to push the Ottomans out of Slavonia, with the use of Pavle, are not successful.

Ferdinand decides to strike a decisive blow in 1537 at John, thereby violating the treaty.

A combined force of Austrians and Bohemians, twenty-four thousand strong, unsuccessfully besieges the Ottoman fortress of Osijek in 1537, in response to depredations by Ottoman soldiers in the region, a violation of the truce of 1533 ending the previous Austro-Turkish War.

The siege, very badly prepared, comes to nothing, because the allied army is decimated by disease and starvation before it can even besiege the city.

The army has to withdraw, and …

…becomes stuck in the swamps of Gorjani, near Đakovo and Valpovo on the Drava river, and their entire heavy armament is lost.

Johann Katzianer flees with the cavalry and abandons his army.

Count Ludwig Lodron remains to engage the Ottoman relief army that has pursued them (led by border commanders), but the entire force is annihilated.

A reported twenty thousand men are killed, including generals Ludwig Lodron and Pavle Bakić.

A disaster of similar magnitude to that of Mohács, this campaign is therefore nicknamed the Austrian Mohacs.

The Ottomans also suspect Moldavia’s current governor of intrigue with Vienna.

Sultan Süleyman therefore renews his war against Vienna.

Turkish inroads in Croatia and Austria also trigger price increases for agricultural goods, and opportunistic landowners begin demanding payment in kind, rather than cash, from serfs.

Rural discontent explodes in 1573 when Matija Gubec leads an organized peasant rebellion that spreads quickly before panic-stricken nobles are able to quell it.

Tough Imperial troops fresh from savage fighting in the Low Countries have come under the supreme command of the Styrian general Ruprecht von Eggenberg.

Their crushing defeat of the Ottoman troops of Bosnian governor-general, or Beylerbeyi, Hasan Pasha Predojević at Sissek (Sisak) on June 22, 1593, enlarges the hostilities into a full-scale war.

Croatian troops are led by the Ban of Croatia, Tamás Erdődy, and some forces from the Duchy of Carniola are led by Andreas von Auersperg (Slovene: Andrej Turjaški), nicknamed the "Carniolian Achilles".

Recent analysis of several hitherto unknown or unused Ottoman sources has shown that there seems to have been a conflict of interest between the policy of the central Ottoman administration and the aims of the belligerent Hasan Pasha.

It appears that the struggle for more land and power was an important incentive for the offensive action on the side of the Bosnian sipahis, an action which at this time is not really in accordance with Constantinople’s policy.

The Sultan, on the other hand, may have felt that such an embarrassing defeat even of a vassal acting independently could not go unavenged if he himself was not to lose face.

The Battle of Sisak is the prelude to the long Second Ottoman-Habsburg War that begins in earnest on July 29, 1593, when the Ottoman army under Sinan Pasha, the Grand Vizier, launches a military campaign against the Habsburg monarchy, marshaling a large army of thirteen thousand Janissaries plus numerous European levies against the Christians.

Western forces had routed a Turkish army besieging Vienna in 1683, then begin driving the Turks from Europe.

In the 1699 Treaty of Karlowitz, the Turks cede most of Hungary, Croatia, and Slavonia to Austria, and by 1718 they no longer threaten Dalmatia.

During the advance, Austria expands its military border, and thousands of Serbs fleeing Turkish oppression settle as border guards in Slavonia and southern Hungary.

As the Turkish threat wanes, Croatian nobles demand reincorporation of the military border into Croatia.

Austria, which uses the guards as an inexpensive standing military force, rejects these demands, and the guards themselves oppose abrogation of their special privileges.