The aim of this article is to analyse the relations of the three Ottoman vassal provinces (Transylvania, Moldavia and Wallachia) during the last years of the Long Turkish War (1591/93–1606). The provinces rebelled against the Ottomans at the beginning of the war. Then influenced by the policies of their dynasties or due to the military occupation of the neighbouring great powers such as the Habsburg monarchy, Poland and the Ottoman Empire, they changed the sides of the conflict. The Movilăs (or Movilă family) tried to govern two Romanian voivodships, Moldavia and Wallachia simultaneously. They had a good relation with the Ottomans and they supported rule of István Bocskai (r. 1604–1606), who rebelled against the Habsburgs in 1604 and was elected as the Prince of Transylvania and Hungary by the Hungarian rebels. The voivode of Wallachia, Radu Şerban (r. 1601, 1602–1610, 1611), who secretly allied himself with the Habsburgs, while simultaneously being recognised by the Ottoman side also endorsed him. The Prince of Moldavia, Ieremia Movilă (r. 1595–1606), tried to remove him from the Wallachian throne. He wanted to install his younger brother, Simion (r. 1600–1602 in Wallachia, r. 1606–1607 in Moldavia) – who had once held the title of the Prince of Wallachia – on the Wallachian throne after deposing of Radu Şerban. They formed an alliance with the Ottoman military dignitaries as well as with Bocskai to achieve their goal. Although this was an unsuccessful attempt, they strongly supported the Hungarian uprising. After the death of Ieremia Movilă, his sons tried to gain the power over Moldavia with Polish assistance. By contrast, the Hungarians gave military assistance to Simion against Ieremia’s sons.