John's reign was marked from the beginning with instability. He came to the throne in June 1280, following the betrayal and death of his brother George (r. 1266–1280) by his own officials. His first recorded act as Emperor was in 1281, when he received an embassy from Michael VIII Palaiologos (r. 1259–1282) consisting of George Acropolites and a prominent churchman by the name of Xiphilinos; the goal of this mission was to convince John to discontinue using the title of "Emperor and Autocrat of the Romans". Michael had gained the throne of the Empire of Nicaea through a coup against the youthful heir John IV Laskaris some 20 years before, then gained possession of Constantinople itself from the Latin Empire, and based on this achievement Michael believed that only he had the right to this title. This was not the only reason the Byzantine emperor regarded John as a threat: some opponents of Michael's acceptance of union with the Western Church saw John as a viable Orthodox candidate for the imperial throne. Michael considered high-ranking members of the Byzantine aristocracy who refused to embrace the union as threats to his reign, and they were imprisoned, flogged, blinded, or murdered.