John II Komnenos
Isaac Komnenos or Comnenus (; 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.