Cosmas II was condemned and deposed on 26 February 1147 by a synod held at the Palace of Blachernae because of indulgence in relation to the monk Niphon, a condemned Bogomil since 1144, whom he received in his home and at his table.[3]
The exact reasons for the conviction and deposition of Cosmas II are not clearly established; perhaps he was the victim of political intrigue.[4] It is clear however that Emperor Manuel I intervened directly in forming the Synod that deposed Cosmas II, interviewing personally those who accused him, and testing Cosmas II directly on his opinions of the heretical Niphon.[5] This affair is typical both of the doctrinal controversies common in the reign of Manuel I and also of the Emperor's readiness to become actively involved in them.[6]