In the years before the American Revolutionary War broke out in April 1775, the Province of Massachusetts Bay had a volunteer militia corps known as the Governor's Company of Cadets. Based in Boston, the company was disbanded in 1774 after its commander, John Hancock, was dismissed by Governor Thomas Gage. A number of its members left the city when the Siege of Boston began, and reformed themselves as an independent company under the command of Lieutenant Colonel Henry Jackson after the British evacuated the city in March 1776.