How long did it last?
There is a lot of disagreement about when the empire began. Some historians say it was as early as the 12th century, when the Normans moved into Ireland. Others say the start date should be the 1490s, while other historians date the empire from the early 1600s. The end of the empire came in the years after World War 2, with most of Britain's colonies ruling themselves independently by the late 1960s.