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.
Decolonization
The independence movement in Ireland and the 19th and early 20th century was marked by occasional outbursts of violence, culminating in the small-scale Easter Rising of 1916 and the much larger Irish War of Independence of 1919 to 1921. It was resolved when London gave independence to the Catholic regions of southern Ireland, and kept control of Protestant Northern Ireland.