Andronikos I Komnenos

Andronikos I Komnenos led a revolt against the regency of Empress Maria of Antioch, entering Constantinople with popular support. He had the empress imprisoned and later executed, and then had the young emperor Alexios II strangled, making himself sole ruler.

Andronikos I instigated a massacre of Latin (Western European) residents in Constantinople, targeting merchants and their families. The violence killed thousands and severely damaged Byzantine relations with the West, contributing to the later Fourth Crusade.

Andronikos I initiated a reign of terror, executing numerous aristocrats and officials he suspected of disloyalty. His purges weakened the Byzantine nobility and military leadership, creating widespread fear and instability within the empire.

Andronikos I was overthrown by a popular uprising in Constantinople led by Isaac II Angelos. He was captured while trying to flee, and the mob subjected him to three days of torture, including having his hand cut off and an eye gouged out, before he was killed in the Hippodrome.