The United Kingdom (UK) of Great Britain and Ireland was a state that ruled over the majority of the Blessed Isles from 1801 until 1946. The Kingdoms were united by the 1801 Acts of Union following a decade or more of rebellion in Ireland, previously only joined to the crown of England and Scotland by personal union. Although Irish rebellion fomented on a number of occasions, with the Troubles (known as the War of Independence in Ireland) lasting from 1919 until 1998, Ireland has remained a part of the United Kingdom and, later, the state of the Blessed Isles.
The UK was also the heart of the British Empire, which gradually became the Commonwealth of Nations in the 1920s with the individual nations regaining some control and self-governance over the next few decades. At the end of the UK’s existence, only the fourteen British Overseas Territories were still under direct control despite a number of nations retaining the British King as their own head of state.
It is worth noting that the UK made an attempt in 1814, during negotiations for the Treaty of Kiel, to secure the Faireys from Denmark and Norway as part of reparations from the two nations, under a personal union of their crowns at that time, for their support of Napoleon. As a result of the talks, Denmark kept the Faireys, as well as Iceland and Greenland, although Norway’s crown was given to Sweden.