In 1193, his father, King Tancred, arranged his marriage to Irene, daughter of the eastern Emperor Isaac II. Tancred then had his son Roger crowned. Roger died the next year, shortly before his father's death on the 20th of February1194. His younger brother William III assumed the throne of Sicily under the regency of his mother Sibylla of Accera.
Isaac inaugurated his reign with a decisive victory over the Norman King of Sicily William II (on the banks of the Strymon, 7 September 1185), who had invaded the Balkans towards the end of Andronicus I's reign.
After eight years of captivity, he was raised from his dungeon to his throne once more after the arrival of the Fourth Crusade and the flight of Alexios III from the capital.
But both mind and body had been enfeebled by confinement, and his son Alexios IV Angelos was associated on the throne as the effective monarch.