At the end of the 15th century, the Tudors initiated actions to strengthen the central English authority over Ireland.

An excerpt from the article 39 facts about Ireland

Henry VIII imposed royal authority on the Church of Ireland (in place of the papacy), and in 1541, he assumed the title of King of Ireland. The administration was expanded according to the English model, and English laws were popularized, breaking local rebellions and those of great families. Resistance to English policy began to coincide with the island's religious division. Anglicanism became the religion of only the new English colonists and the ruling class, while the Irish and the majority of the Anglo-Irish population (the so-called Old English) remained Catholic.