Isaac II Angelus was a Byzantine Emperor who ruled from 1185 to 1195 and again in 1203 to 1204. He was part of the Angelus dynasty and came to power after a coup that deposed his brother, Alexius III. His reign was marked by internal strife and external threats, particularly from the Normans and the Crusaders. In 1195, Isaac II was overthrown by his brother, who took the throne as Alexius III Angelus. After years of exile, Isaac regained power with the help of the Fourth Crusade in 1203. However, his reign ended in 1204 when the Crusaders captured Constantinople, leading to the establishment of the Latin Empire.