Caliphate
Ottoman rulers used the title "Caliph" symbolically on many occasions but it was strengthened when the Ottoman Empire defeated the Mamluk Sultanate in 1517 and took control of most Arab lands. The last Abbasid Caliph at Cairo, al-Mutawakkil III, was taken into custody and was transported to Istanbul, where he reportedly surrendered the Caliphate to Selim I.