Revenue stamps of Northern Ireland
Upon the partition of Ireland in 1921, separate revenue stamps began to be issued for both Northern Ireland and Southern Ireland. The latter were withdrawn soon afterwards upon the establishment of the Provisional Government, but the former continued to issue revenue stamps until the late 20th century. The need for separate issues for Northern Ireland came about since taxes raised there were meant to remain in the country. Most Northern Irish revenue stamps were British key types with appropriate inscriptions, but there were a number of different issues as well.
Military history of Ireland
Until 1922 secret societies, popular risings and guerilla warfare came in sporadic outbreaks in attempts to end the 1801 union of Ireland and Great Britain. Between 1919–1922 the War of Independence brought the negotiation of the Anglo-Irish Treaty and the majority of Ireland seceded from the United Kingdom to form an independent state, which immediately fell into a civil war between opposing republican factions. The northern portion of the country would form Northern Ireland becoming an autonomous part of the United Kingdom.