Religious freedom is constitutionally provided for in Ireland. Christianity is the predominant religion, with the Roman Catholic Church as the largest church. In 2006, 86.8% of the population identified themselves as Roman Catholic, 4.8% as Protestant or another Christian religion, 2% as non-Christian, and 1.6% did not state their religion. According to the 2006 census, the non-religious group has now become the second largest group after Roman Catholic. According to a Georgetown University study, the country has one of the highest rates of regular Mass attendance in the Western World. While daily attendance was 13% in 2006, there was a reduction in weekly attendance from 81% in 1990 to 48% in 2006, although the decline was reported as stabilising. In 2011, it was reported that weekly Mass attendance in Dublin was just 18%, with it being even lower among younger generations.
The Church of Ireland is the second largest Christian denomination. Membership declined throughout the twentieth century, but has recently experienced an increase, as have other small Christian denominations. Significant Protestant denominations are the Presbyterian Church and Methodist Church. Immigration has contributed to a growth in Hindu and Muslim populations. In percentage terms, Orthodox Christianity and Islam were the fastest growing religions, with increases of 100% and 70% respectively.
Ireland's patron saints are Saint Patrick, Saint Bridget and Saint Columba. Saint Patrick is the only one commonly recognised as the patron saint. Saint Patrick's Day is celebrated on 17 March in Ireland and abroad as the Irish national day, with parades and other celebrations.
As with other predominantly Catholic European states, Ireland underwent a period of legal secularisation in the late twentieth century. In 1972, the article of the Constitution naming specific religious groups was deleted by the Fifth Amendment in a referendum. Article 44 still remains in the Constitution:
