The territorial evolution of the British Empire is considered to have begun with the foundation of the English colonial empire in the late 16th century. Since then, many territories around the world have been under the control of the United Kingdom or its predecessor states.When the Kingdom of Great Britain was formed in 1707 by the union of the Kingdoms of Scotland and England, the latter country's colonial possessions passed to the new state. Similarly, when Great Britain was united with the Kingdom of Ireland in 1801 to form the United Kingdom, control over its colonial possessions passed to the latter state. Collectively, these territories are referred to as the British Empire. When much of Ireland gained independence in 1922 as the Irish Free State, the other territories of the empire remained under the control of the United Kingdom.
From 1714 to 1837, the British throne was held by a series of kings who were also the rulers of the German state of Hanover. However, this was purely a personal union, with Hanover maintaining its political independence otherwise, and so it is not usually considered to have formed part of the British Empire.