Religion in the Republic of Ireland
Christianity is the largest religion in the Republic of Ireland based on baptisms. Irish Christianity is dominated by the Catholic Church, and Christianity as a whole accounts for 82.3% of the Irish population. Most churches are organized on an all-Ireland basis which includes both Northern Ireland and the Republic of Ireland.
Irish travellers have traditionally adopted a very particular attitude to the Catholic Church, with a focus on figures such as "healing priests". More generally a tradition of visions continues, often outside of Church sanction.
Catholic Church in Ireland
Christianity has existed in Ireland since the 5th century and arrived from Roman Britain (most famously associated with Saint Patrick), forming what is today known as Gaelic Christianity. It gradually gained ground and replaced the old pagan traditions. The Catholic Church in Ireland cites its origin to this period and considers Palladius as the first bishop sent to the Gaels by Pope Celestine I. However, during the 12th century a stricter uniformity in the Western Church was enforced, with the diocesan structure introduced with the Synod of Ráth Breasail in 1111 and culminating with the Gregorian Reform which coincided with the Norman invasion of Ireland.