sentences:  Croatian military troops fought in many battles under command of Italian Franciscan priest fra John Capistrano, the Hungarian Generalissimo John Hunyadi, and Hungarian King Matthias Corvinus, like in the Hunyadi's long campaign (1443–1444), battle of Varna (1444), second battle of Kosovo (1448), and contributed to the Christian victories over the Ottomans in the siege of Belgrade (1456) and Siege of Jajce (1463).At the time they suffered a major defeat in the battle of Krbava field (Lika, Croatia) in 1493 and gradually lost increasing amounts of territory to the Ottoman Empire.Pope Leo X called Croatia the "forefront of Christianity (Antemurale Christianitatis)" in 1519, given that several Croatian soldiers made significant contributions to the struggle against the Ottoman Turks.