Pope St. Martin I Exercising Papal Jurisdiction In The East
Source: vaticancatholic.com

Pope St. Martin I is recognized as a saint by the Eastern “Orthodox”. In 649 he sent a letter to John, the Bishop of Philadelphia in Arabia, telling him to appoint bishops and priests in the Eastern sees of Jerusalem and Antioch. Heretics had usurped many positions of authority in the East. Pope St. Martin teaches that his apostolic authority, based on what Christ gave to St. Peter, enables him to exercise this power in the Eastern sees. This is another clear example of universal papal jurisdiction in the first millennium.
Pope St. Martin I, To John the Bishop of Philadelphia (in Arabia), Oct. 31, 649: “… you might correct what is deficient and appoint bishops and priests and deacons throughout every city of those which are in the sees of Jerusalem and Antioch. It is fitting for you to do this by the direction of our apostolic authority, which the Lord gave us through the most holy Peter, the prince of the Apostles, on account of the desperate needs of our times and the pressure of the [Arab] tribes…” (Bronwen Neil & Pauline Allen, Conflict And Negotiation In The Early Church, p. 212)