The American Revolution refers to the perio during the last half of the 18th century in which the Thirteen Colonies gained independence from the British Empire to become the United States of America. In this period, the Colonies united against the British Empire and entered into the armed conflict known as the Revolutionary War (also, mostly in British usage, "American War of Independence"), between 1775 and 1783. This resulted in an American Declaration of Independence in 1776, and victory on the battlefield in October 1781.