Seljuk Empire

The Seljuk Empire was a medieval Turco-Persian, Sunni Muslim empire from 1037 until 1194. In the Battle of Manzikert in 1071, it defeated the Byzantine Empire, making the Byzantines unable to defend their borders and opening the door to Seljuk expansion into Anatolia.

Because of later Mongol invasions of Anatolia, the sultanate was divided into smaller emirates called beyliks. One of these beyliks was the Ottomans, who eventually rose to power and conquered all other beyliks. The Ottomans eventually conquered Constantinople under Mehmet I (The Conqueror), who became the first sultan of the Ottoman Empire.