During the 13th and 14th century, the Ottoman state carried out a more serious territorial expansion. The expansion of the Ottoman state to the Balkan Peninsula began during the 14th and 15th century upon the reign of Sultan Murat II. Murat's son, Sultan Mehmed II, by conquering Constantinople achieved the, until then, unattainable goal of the Ottoman ancestors, which is why he remained known in historiography by the nickname Conqueror. He focused his unlimited and absolute governmental power on the Balkan Peninsula, where he used different principles of government from previous sultans to exploit the economic and political situations of the 15th century, such as strengthening the Balkan greats, which Sultan Mehmed II. harmonized in the principle of management of remote Ottoman territory. The anti-Ottoman coalitions encouraged by the Roman Catholic Church were unsuccessful in their intention to expel the Ottomans from European territory. The Ottoman subordination of the Balkan countries to the Empire took place during the second half of the 15th century. The Republic of Dubrovnik has successfully reached disputes with the Ottomans, and neutrality in conflicts and loyalty to lay and clerical rulers have enabled it to move and trade freely throughout European territory. During Ottoman activity in the hinterland, Dubrovnik feared for their country, but the fate of destruction or direct subordination bypassed them for diplomatic experience and skill. Sultan Mehmed II. The Conqueror died in 1481. during the occupation of South Italian territory.