Battle of Manzikert

In August 1071, Byzantine Emperor Romanos IV Diogenes confronted Seljuk Sultan Alp Arslan near Manzikert in eastern Anatolia. Internal betrayals undermined the Byzantine force: Turkmen auxiliaries defected to the Seljuks, and General Andronikos Doukas withdrew his rearguard during the engagement. Romanos was captured and released after agreeing to territorial concessions and tribute payments. The defeat opened Anatolia to Turkic settlement, leading to the establishment of the Sultanate of Rum by approximately 1078. The resulting instability was among the factors that prompted Pope Urban II to call the First Crusade in 1095.