who had died in 1206. Laskaris had established a Byzantine Greek successor state in Asia, the Empire of Nicaea, and had tried to persuade John X to join him, but he had refused because of old age and died shortly after.

Shortly after his appointment, on 20 March 1208, Michael IV performed Theodore I Laskaris' coronation as emperor (Laskaris had already been acclaimed emperor in 1205). He also took the highly unusual move, contrary to both Byzantine tradition