This is rather peculiar. Patrick got the Orthodox imprimatur because his testimony to papal authority was not used by the Latins against the defenders of schism. Hardly qui tacit consentire. Saint Patrick was not dealing with heresies or schisms in Ireland, but with paganism, and he converted the whole island to the One, True Church under the Vicar of Christ. Protestant divines have tried to claim Saint Patrick as one of their own, an independent missioner, unauthorized by Rome. That this is nonsense is proven by all Catholic biographies of the saint, who was commissioned by Pope Saint Celestine I in 432 to assist Saint Palladius, who was the bishop of Ireland. Palladius, however, died before Saint Patrick left Gaul and, while still there, hearing this news, he was consecrated bishop by Saint Germanus. Only a generation after Saint Patrick’s death in 493, we have a letter written by Saint Columbanus, a disciple of Patrick’s disciples, to Pope Boniface IV, in which he stressed the Irish Church’s loyalty to Rome thusly:
“Writing to Pope Boniface IV, Columbanus directs his epistle “to the most lovely of all Europe ; to the Head of all the Churches ; to the exalted prelate ; to the pastor of pastors ” ; and in the letter he says that “we Irish are disciples of SS. Peter and Paul and of all the divinely inspired canonical writers, adhering constantly to the evangelical and apostolical doctrine. Amongst us neither Jew, heretic nor schismatic can be found, but the Catholic faith unaltered, unshaken, precisely as we have received it from you, who are the successors of the apostles. For as I have already said, we are attached to the chair of Peter; and although Rome is great and renowned, yet with us it is great and illustrious only on account of that apostolical chair. Through the two apostles of Christ you are almost celestial, and Rome the head of all the Churches of the world.” (The Sacred Heart Review, Volume 15, Number 11, 14 March 1896) For the full article proving the apostle of Ireland’s Roman commission go here.
Catholic Herald: The Russian Orthodox Church has added St Patrick to its calendar of saints. The fifth-century saint, known as the apostle of Ireland, was one of 15 names added to the Russian Orthodox menology. The saints all lived in western and central Europe prior to the Great Schism of 1054. More here.