Michael VIII's personal envoy announced at the Council of Lyon on 6July that he had accepted the Catholic creed and papal primacy. About three weeks later, Pope Gregory again prohibited Charles from launching military actions against the Byzantine Empire. The Pope also tried to mediate a truce between Charles and Michael, but the latter chose to attack several smaller states in the Balkans, including Charles' vassals. The Byzantine fleet took control of the maritime routes between Albania and southern Italy in the late 1270s. Gregory only allowed Charles to send reinforcements to Achaea. The organisation of a new crusade to the Holy Land remained the Pope's principal object. He persuaded Charles to start negotiations with Maria of Antioch about purchasing her claim to the Kingdom of Jerusalem. The High Court of Jerusalem had already rejected her in favour of Hugh III of Cyprus, but the Pope had a low opinion of Hugh.