The Latin patriarch of Antioch, Alberto Brescia Rezzato, died during the Council of Lyon and sometime before 22 July 1246 Pope Innocent named his nephew to succeed him. In October 1247, Opizzo was named apostolic delegate to the Seventh Crusade but he did not leave Genoa for the east until mid-1248. By then, he had secured papal approval of his authority over all bishops suffragan to the Greek patriarch of his city; upon arriving in Antioch, he excommunicated Euthymius, who was forced to flee. In late 1248, amid the Seventh Crusade, Opizzo requested help from the French king following raids by the Turcomans; Louis granted the bishop and his lord Bohemond 600 crossbowmen but no knights, out of "fear that the army might break up and that it would prove impossible to reassemble it at the scheduled time." A papal letter of 7 November 1252 directed him to recognize that Prince Bohemond had reached the age of majority and no longer required the regency of his mother, Luciana Segni. Letters of 30 March 1254 granted him the church of Nicosia and—on account of the expenses occasioned by his visits to the Roman Curia where he was a professor of law—a portion of the income of the late bishop of Norwich and half the subsidies being directed to the aid of Antioch. He was at Acre in October 1254.