Selim I

To secure his succession, Selim I ordered the execution of his brothers, Prince Mustafa and Prince Korkut, who were potential rivals for the throne. This act followed the Ottoman practice of fratricide to prevent civil war. It eliminated internal opposition and consolidated Selim's rule.

Selim I led the Ottoman army against the Safavid Empire under Shah Ismail I at Chaldiran in eastern Anatolia. The Ottomans, using superior artillery and gunpowder tactics, decisively defeated the Safavids. This victory secured Ottoman control over eastern Anatolia and prevented Safavid expansion westward.

Selim I led a campaign against the Mamluk Sultanate, defeating them at the Battle of Marj Dabiq and the Battle of Ridaniya. He conquered Cairo and the Hejaz, including the holy cities of Mecca and Medina. This brought the Islamic caliphate under Ottoman control and expanded Ottoman territory into North Africa and Arabia.

After conquering Cairo, Selim I received the keys to the Kaaba and the relics of the Prophet Muhammad from the last Abbasid caliph, Al-Mutawakkil III. Selim I assumed the title of Caliph, claiming spiritual leadership of the Islamic world. This transfer established the Ottoman sultans as caliphs until 1924.