Isaac II was born in September, 1156 in Istanbul, Turkey. His father Andronikos Doukas Angelos was a military leader in Asia Minor (c. 1122 - aft. 1185) who married Euphrosyne Kastamonitissa (c. 1125 - aft. 1195). Andronikos Doukas Angelos was the son of Constantine Angelos and Theodora Komnene (b. 15 January 1096/1097), the youngest daughter of Emperor Alexios I Komnenos and Irene Doukaina. Thus Isaac was a member of the extended imperial clan of the Komnenoi.
Isaac II inaugurated his reign by a decisive victory over the Normans in Sicily, but elsewhere his policy was less successful. He failed in an attempt to recover Cyprus from a rebellious noble, and by the oppressiveness of his taxes drove the Bulgarians and Vlachs to revolt (1186). In 1187 Alexis Branas, the general sent against the rebels, treacherously turned his arms against his master, and attempted to seize Constantinople, but was defeated and slain. The emperor's attention was next demanded in the east, where several claimants to the throne successively rose and fell. In 1189 Frederick Barbarossa of Germany sought and obtained leave to lead his troops on the third crusade through the Byzantine territory; but he had no sooner crossed the border than Isaac, who had meanwhile sought an alliance with Saladin, threw every impediment in his way, and was only compelled by force of arms to fulfil his engagements. The next five years were disturbed by fresh rebellions of the Vlachs, against whom Isaac led several expeditions in person. During one of these, in 1195, Alexius, the emperor's brother, taking advantage of the latter's absence from camp on a hunting expedition, proclaimed himself emperor, and was readily recognised by the soldiers. Isaac was blinded and imprisoned in Constantinople. After eight years of captivity, Isaac II was raised from the dungeon to the throne once more after the arrival of the Fourth Crusade and the flight of Alexios III from the capital. Both his mind and body had been enfeebled by confinement, and his son Alexios IV Angelos was associated on the throne as the effective monarch. Heavily beholden to the crusaders, Alexios IV was unable to meet his obligations and his vacillation caused him to lose the support of both his crusader allies and his subjects. At the end of January 1204 the influential court official Alexios Doukas Mourtzouphlos took advantage of riots in the capital to imprison Alexios IV and seize the throne as Emperor Alexios V. At this point Isaac II died, allegedly of shock, while Alexios IV was strangled on 28 or 29 January.
Isaac has the reputation as one of the most unsuccessful princes to occupy the Byzantine throne. Surrounded by a crowd of slaves, mistresses, and flatterers, he permitted his empire to be administered by unworthy favourites, while he squandered the money wrung from his provinces on costly buildings and expensive gifts to the churches of his metropolis. During his reign the Empire lost Lefkada, Kefallonia, and Zakynthos to the Normans in 1185. In the same year the Bulgarian Empire was restored after the rebellion of the brothers Asen and Peter, thus losing Moesia and parts of Thrace and Macedonia. After that Cilicia was retaken by the Armenians, and Cyprus wrested from the empire by the Franks.
The identity of Isaac II's first wife is unknown, but her name, Herina (i. e. , Irene), is found on the necrology of Speyer Cathedral, where their daughter Irene is interred. Isaac's wife may have been a member of the Palaiologos family. A possible foreign origin is also given to her due to having the same name as her daughter. Their third child was born in 1182 or 1183 and she was dead or divorced by 1185, when Isaac remarried. By his second wife, Margaret of Hungary, Isaac II had two sons.
He was a Byzantine aristocrat related to the ruling Komnenos dynasty.
He was Byzantine Emperor from March 1195 to July 17/18, 1203.
