| Isaac Komnenos | |
|---|---|
| Sebastokrator of the Byzantine Empire | |
&sq=Qlik&lang=&file=File:Isaac_Komnenos_the_Porphyrogennetos.jpg) Mosaic of Isaac Komnenos the porphyrogennetos from the Chora Church | |
| Born | 16 January 1093 Constantinople |
| Died | after 1152 |
| Spouse | Irene |
| Issue | John Tzelepes Komnenos Andronikos I Komnenos |
| Dynasty | Komnenoi |
| Father | Alexios I Komnenos |
| Mother | Irene Doukaina |
Isaac Komnenos or Comnenus (Greek: Ἰσαάκιος Κομνηνός, romanized: Isaakios Komnēnos; 16 January 1093 – after 1152) was the third son of Byzantine Emperor Alexios I Komnenos and Empress Irene Doukaina. He was raised to the high rank of sebastokrator by his older brother John II Komnenos in reward for his support, but they later fell out, as Isaac began to covet the throne.
In 1130, Isaac and his sons fled to exile after becoming involved in a conspiracy against John. For several years, they wandered in Asia Minor and the Levant, trying to gain support from the local rulers, which was ultimately in vain. John's military successes forced Isaac to seek a reconciliation with his brother in 1138, although he did not give up his designs on the throne. In 1139, after his oldest son defected to the Seljuk Turks, Isaac was exiled to Heraclea Pontica. During the succession struggle that followed John's death in 1143, he supported the unsuccessful candidacy of his elder nephew, likewise named Isaac, over his younger nephew Manuel I Komnenos.
Weakened by the onset of an illness, he was forced to retire from public life by Manuel in 1150. Isaac then devoted himself to the construction of the monastery of Theotokos Kosmosoteira at Bera (modern Feres) in western Thrace, where he was to be buried. Isaac was noted for his erudition and his patronage of learning, and is considered the author of a number of scholarly and poetic works. He is also notable for rebuilding the Chora Church in Constantinople, where his mosaic donor portrait survives to this day. His younger son Andronikos I Komnenos eventually managed to realize Isaac's ambitions, becoming emperor in 1183–1185, the last of the Komnenian dynasty.