Career
The contemporary historian Niketas Choniates describes him as a brave, audacious and experienced soldier but frequently led astray by his foolhardiness and presumption. The rebels did not oppose the Byzantines in the open field, and instead retired to their mountain stronghold. John followed them there, but due to his overconfidence neglected to fortify his camp and allowed it to be surrounded, suffering a humiliating defeat.
His robes of office were captured and displayed by the Bulgarian leaders Peter and Asen.
John was relieved of command by the Emperor in favour of Alexios Branas, and lived in retirement. The marriage was first disallowed by the Patriarch Luke Chrysoberges and the then-reigning Emperor Manuel I Komnenos (r 1143–1180), because a seventh degree of consanguinity existed between John and Eirene.
However in 1185-1186, after Isaac Angelos came to power, a synod overthrew Patriarch Basil II Kamateros—an appointee of Andronikos I—and the new Patriarch, Niketas Mountanes, gave his approval to the marriage. They appear to have had a son, for the man was put forth as a possible candidate to the throne during the illness of Alexios III.