Selim I (Selim the Grim) (sĕlĬm´), 1467–1520, Ottoman sultan (1512–20). He ascended the throne of the Ottoman Empire by forcing the abdication of his father, Beyazid II, and by killing his brothers. A religious controversy (see Sunni and Shiites) and Persian support for his brother Ahmed led Selim, a Sunni, to attack Persia. In 1514 he defeated the Shiite conqueror of Persia, Shah Ismail, annexing Diyarbekir and Kurdistan. This began the enduring rivalry between Persians and Ottomans. Aided by his superior artillery, Selim defeated (1516–17) the Mamluks in Syria and Egypt, which he added to the Ottoman Empire. By assuming the caliphate, Selim made himself and his successors spiritual as well as temporal heads of the empire and gained control over the holy cities of Mecca and Medina. Selim died while preparing the conquest of Rhodes. Under him the Ottoman Empire entered the period of its greatest power. His son, Sulayman I, succeeded him.