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 The latter were withdrawn soon afterwards upon the establishment of the Provisional Government, but the former continued to issue revenue stamps until the late 20th century.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.
Monarchy of the United Kingdom
In 1800, as a result of the Irish Rebellion of 1798, the Act of Union merged the kingdom of Great Britain and the kingdom of Ireland into the United Kingdom of Great Britain and Ireland. The whole island of Ireland continued to be a part of the United Kingdom until 1922, when what is now the Republic of Ireland won independence as the Irish Free State, a separate Dominion within the Commonwealth. The Irish Free State was renamed Éire (or "Ireland") in 1937, and in 1949 declared itself a republic, left the Commonwealth and severed all ties with the monarchy. Northern Ireland remained within the Union. In 1927, the United Kingdom changed its name to the United Kingdom of Great Britain and Northern Ireland, while the monarch's style for the next twenty years became "of Great Britain, Ireland and the British Dominions beyond the Seas, King, Defender of the Faith, Emperor of India".