The Long War or Fifteen Years' War (1591 or 1593 1604 or 1606) was one of the numerous wars between the Habsburg Monarchy and the Ottoman Empire that took place after the Battle of Mohács. The main participants of this war were the countries forming the Habsburg Monarchy ( Austria, Royal Hungary, Croatia, Bohemia ), Transylvania, Wallachia, Moldavia and the Ottoman Empire. Ferrara, Tuscany, Mantua and the Papal State also became involved in the war to some extent. After intesifying skirmishes from 1591, the war started on July 29, 1593 when the Ottoman army under Sinan Pasha launched a military campaign against the Habsburg monarchy. In 1595, a Christian alliance of European powers was organized by Pope Clement VIII against the Turkish, and a treaty of alliance was signed in Prague by the Holy Roman Emperor, Rudolf II and Sigismund Báthory of Transylvania, to which Aron Vod of Moldavia and Michael the Brave of Walachia joined. The objective of the war on behalf of the Ottoman Empire was to seize Vienna, while the Habsburg Monarchy wanted to liberate the central territories of the Kingdom of Hungary occupied by the Ottoman Empire.