 After Constantine the Great had enlarged Byzantium to make it into a second capital city in 330, it was thought appropriate that its bishop, once a suffragan of the Exarch of Thrace and Macedonia, the Metropolitan of Heraclea, should be elevated to an archbishopric.For many decades the heads of the church of Rome opposed this ambition, not because anyone thought of disputing their first place, but because they defended the 'Petrine principle' by which all Patriarchates were derived from Saint Peter and were unwilling to violate the old order of the hierarchy for political reasons.In 381, the First Council of Constantinople declared that "The Bishop of Constantinople shall have the primacy of honour after the Bishop of Rome, because it is New Rome" (canon iii).