On April 18, 1949, Britain recognized Ireland's independence. On April 18, 1949, Britain recognized Ireland's independence. Today, 3000 BC, European continental immigrants began to settle on the island of Ireland. The 12th century entered the feudal society. In 1169 Britain invaded. In 1171 King Henry became the monarch of Ireland. In 1801, Great Britain and the United Kingdom of Ireland were founded, and Ireland was annexed by Britain. In 1966, Dublin erupted the "Easter festival" of anti-British rule. On December 6, 1921, Britain was forced to sign a treaty with Ireland, with the exception of the six northern counties left outside of Britain, and the 26 southern counties established a "free state", enjoying the right to self-government. In 1937, Ireland declared