towns. Gunfire erupted again between the two sides and continued throughout the day as the regulars marched back towards Boston. Upon returning to Lexington, Lt. Col. Smith's expedition was rescued by reinforcements under Brigadier General Hugh Percy, a future Duke of Northumberland styled at this time by the courtesy title Earl Percy. The combined force of about 1,700 men marched back to Boston under heavy fire in a tactical withdrawal and eventually reached the safety of Charlestown. The accumulated militias then blockaded the narrow land accesses to Charlestown and Boston, starting the siege of Boston. Ralph Waldo Emerson describes the first shot fired by the Patriots at the North Bridge in his "Concord Hymn" as the "shot heard round the world". Background The British Army's infantry was nicknamed "redcoats" and sometimes "devils" by the colonists. They had occupied Boston since 1768 and had been augmented by naval forces and marines to enforce what the colonists called The Intolerable Acts of 1774, which had been passed by the British Parliament to punish the Province of Massachusetts Bay for the Boston Tea Party and other acts of protest. General Thomas Gage was the military governor of Massachusetts and commander-in-chief of the roughly 3,000 British military forces garrisoned in Boston. He had no control over Massachusetts outside of Boston, however, where the implementation of the Acts had increased tensions between the Patriot Whig majority and the pro-British Tory minority. Gage's plan was to avoid conflict by removing military supplies from Whig militias using small, secret, and rapid strikes. This struggle for supplies led to one British success and several Patriot successes in a series of nearly bloodless conflicts known as the Powder Alarms. Gage considered himself to be a friend of liberty and attempted to separate his duties as governor of the colony and as general of an occupying force. Edmund Burke described Gage's conflicted relationship with Massachusetts by saying in Parliament, "An Englishman is the unfittest person on Earth to argue another Englishman into slavery." The colonists had been forming militias since the very beginnings of Colonial settlement for the purpose of defense against Indian attacks. These forces also saw action in the French and Indian War between 1754 and 1763 when they fought alongside British regulars. Under the laws of each New England colony, all towns were obligated to form militia companies composed of all males 16 years of age and