Partition of Ireland
The partition of Ireland () divided the island of Ireland into two distinct jurisdictions, Northern Ireland and Southern Ireland. It took place on 3 May 1921 under the Government of Ireland Act 1920. Today the former is still known as Northern Ireland and forms part of the United Kingdom, while the latter is now a sovereign state also named Ireland and sometimes called the Republic of Ireland.
Irish republicanism
In 1948, Fianna Fáil went out of office for the first time in sixteen years. John A. Costello, leader of the coalition government, announced his intention to declare Ireland a republic. The Republic of Ireland Act 1948, which "described" the state as the Republic of Ireland (without changing its name), led the British government to pass the Ireland Act 1949, which declared that Northern Ireland would continue as part of the United Kingdom unless the Parliament of Northern Ireland consented to leave; and Ireland ceased to be a member of the Commonwealth. As a result of this—and also because continuing struggle against the Dublin government was futile—the republican movement took the decision to focus on Northern Ireland from then on. The decision was announced by the IRA in its Easter statement of 1949.