<P> 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 Conqueror 's conquest of Constantinople , the seat of the Ottomans moved to Constantinople , present - day Istanbul . In 1517 , the Ottoman sultan Selim I defeated and annexed the Mamluk Sultanate of Cairo into his empire . Through conquering and unifying Muslim lands , Selim I became the defender of the Holy Cities of Mecca and Medina , which further strengthened the Ottoman claim to the caliphate in the Muslim world . Ottomans gradually came to be viewed as the de facto leaders and representatives of the Islamic world . However , the earlier Ottoman caliphs did not officially bear the title of caliph in their documents of state , inscriptions , or coinage . It was only in the late eighteenth century that the claim to the caliphate was discovered by the sultans to have a practical use , since it allowed them to counter Russian claims to protect Ottoman Christians with their own claim to protect Muslims under Russian rule . </P>
<P> 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 Conqueror 's conquest of Constantinople , the seat of the Ottomans moved to Constantinople , present - day Istanbul . In 1517 , the Ottoman sultan Selim I defeated and annexed the Mamluk Sultanate of Cairo into his empire . Through conquering and unifying Muslim lands , Selim I became the defender of the Holy Cities of Mecca and Medina , which further strengthened the Ottoman claim to the caliphate in the Muslim world . Ottomans gradually came to be viewed as the de facto leaders and representatives of the Islamic world . However , the earlier Ottoman caliphs did not officially bear the title of caliph in their documents of state , inscriptions , or coinage . It was only in the late eighteenth century that the claim to the caliphate was discovered by the sultans to have a practical use , since it allowed them to counter Russian claims to protect Ottoman Christians with their own claim to protect Muslims under Russian rule . </P>
when did the claim to the caliphate become central to ottoman ideology
when did the claim to the caliphate become central to ottoman ideology
1517
1517