The Ottoman–Habsburg wars were fought from the 16th to the 18th centuries between the Ottoman Empire and the Habsburg monarchy, which was at times supported by the Kingdom of Hungary, Polish–Lithuanian Commonwealth, The Holy Roman Empire, and Habsburg Spain. The wars were dominated by land campaigns in Hungary, including Transylvania (today in Romania) and Vojvodina (today in Serbia), Croatia, and central Serbia.
By the 16th century, the Ottomans had become a serious threat to European powers, with Ottoman ships sweeping away Venetian possessions in the Aegean and Ionian seas and Ottoman-supported Barbary pirates seizing Spanish possessions in the Maghreb. The Protestant Reformation, French–Habsburg rivalry and the numerous civil conflicts of the Holy Roman Empire distracted Christians from their conflict with the Ottomans. Meanwhile, the Ottomans had to contend with Safavid Empire and also to a lesser extent the Mamluk Sultanate, which was defeated by the Ottomans under Selim I rule and later fully incorporated into the empire.