Battle of Manzikert
Also called: Battle of Malazgirt
The Seljuk sultan Alp Arslan routed the Byzantine army at Manzikert in eastern Anatolia and took Emperor Romanos IV prisoner.

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After entering Baghdad in 1055, the Seljuk Turks pressed west into Armenia on the eastern frontier of the Byzantine Empire. Emperor Romanos IV Diogenes marched east with a large army, but one made up largely of mercenaries and poorly united. In August 1071 at Manzikert, north of Lake Van, Alp Arslan’s Seljuk army inflicted a heavy defeat and captured the emperor. Released on promise of a ransom and a treaty, Romanos lost his throne to a coup in the capital.
While Byzantium was torn by civil strife, Turkish nomads poured onto the Anatolian plateau, and a branch of the Seljuks founded the Sultanate of Rum, first at Nicaea and later centred on Konya. From this time Anatolia gradually became a Turkish land, laying the ground for the later rise of the Ottomans. Hard pressed, the Byzantine emperor Alexios I appealed to western Europe for help, and the Crusades began.