Claim: The Ottomans, with an army 38,000 strong, commanded by the Bosnian Beyelerbey Tamas Erdody, needed to win the Battle of Sisak in order to expand northward into central Europe virtually unopposed
Evidence: The Ottoman wars in Europe were a series of military conflicts between the Ottoman Empire and various European states dating from the Late Middle Ages up through the early 20th century. The earliest conflicts began during the Byzantine–Ottoman wars, waged in Anatolia in the late 13th century before entering Europe in the mid 14th century, followed by the Bulgarian–Ottoman wars the Serbian–Ottoman wars waged beginning in the mid 14th century and the Albanian-Turkish wars 1432-1479. Much of this period was characterized by Ottoman expansion into the Balkans. The Ottoman conquest of Bosnia and Herzegovina was a process that started roughly in 1386, when the first Ottoman attacks on the Kingdom of Bosnia took place. In 1451, more than 65 years after its initial attacks, the Ottoman Empire officially established the Bosansko Krajište, an interim borderland military administrative unit, an Ottoman frontier, in parts of Bosnia and Herzegovina. In 1463, the Kingdom fell to the Ottomans, and this territory came under its firm control. The Battle of Sisak (Croatian: Bitka kod Siska; Slovene: Bitka pri Sisku; German: Schlacht bei Sissek; Turkish: Kulpa Bozgunu) was fought on 22 June 1593 between Ottoman regional forces of Telli Hasan Pasha, a notable commander (Beglerbeg) of the Eyalet of Bosnia, and a combined Christian army from the Habsburg lands, mainly Kingdom of Croatia and Inner Austria. The battle took place at Sisak, central Croatia, at the confluence of the rivers Sava and Kupa. The Croatian troops were led by the Ban of Croatia, Thomas Erdődy, and major forces from the Duchy of Carniola and the Duchy of Carinthia were led by Andreas von Auersperg, nicknamed the "Carniolan Achilles". Count Tamás Erdődy de Monyorókerék et Monoszló (Hungarian: monyorókeréki és monoszlói gróf Erdődy Tamás, Croatian: Toma Bakač Erdedi; 1558 – 17 January 1624), also anglicised as Thomas Erdődy, was a Hungarian-Croatian nobleman, who served as Ban of Croatia between 1583-1595 and 1608-1615 and a member of the Erdődy magnate family. He scored significant victories in wars against the Ottoman Empire's armies. When Ottoman forces tried to retake the area in 1593, the battle of Sisak ensued in which the Holy Roman Empire defeated the Ottoman Empire, severely hampering the Ottoman's ability to expand further into Europe and triggering the Long Turkish War. For this victory Erdődy received congratulations from Pope Clement VIII and was knighted into the Order of Saint Saviour by Philip II of Spain. They made a surprise attack on the besieging forces on 22 June. The ensuing battle resulted in a crushing defeat for the regional Ottoman forces, triggering the Long War. The central authorities of both the Ottoman Empire and the Habsburg Monarchy were rather reluctant to fight each other after several campaigns on Hungarian and Moldavian land and four renewals of the 1547 truce, but large scale raids were being mounted into each other's territories: There had been numerous raids into Habsburg Hungary by the akıncı, the irregular Ottoman light cavalry, and on the other hand; Uskoci (Balkan Habsburg-sided irregular soldiers on the eastern Adriatic coast) were being encouraged to conduct raids into Ottoman territory in the Balkans. During this period Ottoman Bosnian forces had made several attempts to seize major forts and towns across the Una and Sava rivers. In August 1591, without a declaration of war, Telli Hasan Pasha, Ottoman beylerbey of the Eyalet of Bosnia and vizier, attacked Croatia and reached Sisak, but was repelled after four days of fighting. Tamás Erdődy, Ban of Croatia, launched a counterattack and seized much of the Moslavina region. The camp had around 3,000 men, while the Ottoman forces had around 7–8,000.