Isaac Komnenos (son of John II)

He participated in the campaigns of his father and brother in Asia Minor, and was a fervent adherent of Patriarch Cosmas II of Constantinople, but little else is known about his life.

[1] He was a tall and imposing man, but, according to the Byzantine sources—who are admittedly partial to his youngest brother and eventual successor to John II, Manuel I Komnenos (r. 1143–1180)—prone to sudden outbursts of anger and harsh punishments, so that he was not much loved.

[5] The contemporary Latin historian William of Tyre, on the other hand, plainly states that the main factor was Manuel's presence with the army and his ability to lead them safely home, while Isaac was away in Constantinople.

[5] Isaac's presence in Constantinople, with his access to the imperial palace and its treasures, including the regalia, posed a considerable threat to Manuel's position.

[10][11] In 1145–1146, Isaac accompanied his brother on campaign against the Sultanate of Rum's capital, Ikonion, as one of the senior commanders of the army, along with John Axouch.

[10][12] According to John Kinnamos, at the emperor's table during that campaign a heated debate occurred, with comparisons being made between the martial qualities of Manuel and his father.