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.
The unit's surgeon from 1779 onward was Dr. James Thacher, who kept an extensive journal of his war experience.
The regiment left Boston in October 1777 to join General George Washington's Main Army outside Philadelphia.
It remained in Rhode Island in 1779, but was despatched to Boston as part of a mobilization made in response to the British seizure of Castine, Maine.