Religion in the Republic of Ireland
The predominant religion in the Republic of Ireland is Christianity, with the largest church being the Roman Catholic Church. The Irish constitution says that the state may not endorse any particular religion and guarantees freedom of religion.
Eastern Orthodoxy in the Republic of Ireland
From the Orthodox perspective, the Irish Church was Orthodox prior to the Great Schism of 1054. Since the Gregorian Reforms did not immediately reach Ireland until the beginning of the twelfth century with the four great reforming synods of Cashel I (1101), Ráth Breasail (1111), Kells-Mellifont (1152), and Cashel II (1172), Ireland's progress away from her ancient communion with the rest of the Christian East was extremely slow and likely not felt in many isolated Christian communities until some time after the arrival of the Normans. Therefore, the great golden age of Irish saints and scholars is seen by the Orthodox as being Ireland's era of her true Christian Orthodoxy, as it was only after Ireland accepted the papal reforms that this golden period of intense asceticism ceased, and new, Roman Catholic orders of monasticism were introduced from the Continent. In recognition of this, Orthodox Patriarchates have begun to emphasize pre-schism Irish saints in their worship, and even building churches dedicated to them.