 It could be concluded from Ottoman sources that the main initiators and leaders of the uprising once belonged to the Christian layers in Ottoman military service.After the Ottoman conquest of Gyula in 1566, these began to lose their privileges and became part of the lower class ("raja"); a part moved to Transylvania and the frontier parts of the empire, a part stayed, while a large number joined "hajduk" bands.The defeat of the Ottomans at the Battle of Sisak (22 June 1593) and the uncertain outcome of fighting in Upper Hungary in the beginning of the Long Turkish War (1593–1606) woke up internal problems and also jeopardized Ottoman rule in the vassal principalities of Transylvania, Wallachia and Moldavia.