 Complete the following phrase:  The caliphate was claimed by the sultans of the Ottoman Empire beginning with Murad I reigned 1362 to 1389, while recognising no authority on the part of the Abbasid caliphs of the Mamluk-ruled Cairo. Hence the seat of the caliphate moved to the Ottoman capital of Edirne. In 1453, after Mehmed the Conquerors 