Isaac Komnenos (son of John II)

Isaac Komnenos or Comnenus (Greek: Ἰσαάκιος Κομνηνός, Isaakios Komnēnos; c. 1113 – after 1154), was the third son of Byzantine Emperor John II Komnenos by Piroska of Hungary.

Shortly before his death in 1143, John II Komnenos designated his fourth son Manuel as his heir, although the third son, Isaac, was still alive. At the time Isaac was conducting the body of his eldest brother, the co-emperor Alexios Komnenos, back to Constantinople.

Manuel had the powerful backing of the megas domestikos (commander-in-chief of the army) John Axuch who took control of the capital before Isaac learned of his father's death and could make any bid for the throne. Axuch was faithful to the wishes of John II, although he is recorded as having tried hard to persuade the dying emperor that Isaac was the better candidate to succeed. Although some of the clergy, the people and the military, thought that Isaac was better fit to rule, he had to resign himself to his younger brother's accession.

In 1145–1146 he campaigned with him against the Seljuk Turks in Anatolia. Although the relationship between the brothers remained uneasy, there was never an open conflict, and Isaac enjoyed the court dignity of sebastokrator. The marriages of Isaac's daughters served as useful tools of Manuel's foreign policy.

By his first wife, Theodora Kamaterina (d. 1144), Isaac had five children:

• Alexios Komnenos (d. c. 1136).
• Ioannes Komnenos (d. c. 1136/7).
• Eirene Komnene, who married an unnamed Doukas Kamateros and became the mother of Isaac Komnenos of Cyprus.
• Anna Komnene, who married before 1166 Constantine Makrodoukas (d. 1185).
• Maria Komnene, who married in 1156 King Stephen IV of Hungary.

By his second wife, Eirene Diplosynadene, whom he married in 1146, Isaac had two daughters:

• Theodora Komnene (b. 1145/6), who was the lover of Emperor Andronikos I Komnenos and married in 1158 King Baldwin III of Jerusalem.
• Eudokia Komnene, who married William VIII of Montpellier.