The Catholic Church in Ireland kept alive the Irish spirit over 800 years of domination by England.  When Strongbow (the ancestor of the Fitzgerald's) invaded Ireland in the 12th century, most of the country remained under Irish law.  The Normans created major lordships through the Fitzgerald's, the Butlers, the Fitzgibbons and others; but it wasn't until Henry VIII that Catholicism was outlawed and replaced by the Church of England as the state religion.  From Henry's time to 1922, the Church remained one of the few obstacles between Irish independence and complete dominance by English interests.