During the Siege of Boston, Castle William served as the main base of military operations for the British. The leaders of the Massachusetts royal administration took refuge there with their families, as did some prominent loyalists or "tories." Major Pelham Winslow of the prominent loyalist town of Marshfield, Massachusetts was the Commander of Castle William for a time during the Revolution. After the British Evacuation of Boston on March 17, 1776, Castle William was destroyed. After the fort was destroyed, Lieutenant Paul Revere was put in charge of rebuilding it. The rebuilt fort was named Fort Independence on December 7, 1797.