Extract the answer to the question from the following context. Question: The American War of Independence kicked off what major period for the American colonies, later the United States? Context: Beginning the Age of Revolution, the American Revolution and the ensuing political upheaval during the last half of the 18th century saw the Thirteen Colonies of North America overthrow the governance of the Parliament of Great Britain, and then reject the British monarchy itself to become the sovereign United States of America. In this period the colonies first rejected the authority of the Parliament to govern them without representation, and formed self-governing independent states. The Second Continental Congress then joined together against the British to defend that self-governance in the armed conflict from 1775 to 1783 known as the American Revolutionary War (also called American War of Independence).
A:
Age of Revolution