Discontent in Britain’s Thirteen Colonies had built to open violence by the mid-1770s, much of it occurring in and around Boston. (See Map 19.) A lack of representation and perceptions that British leaders pursued overbearing policies because they were indifferent or even hostile to the plight of the inhabitants pushed ever more colonists towards open rebellion. In response, the tools Britain possessed to confront its colonial troubles were limited by the nature of its government and the few instruments at its disposal. These included the army and navy, but their use at Boston only exacerbated tensions. Fighting flared on 19 April 1775 when British soldiers attempted to seize munitions at Concord, Massachusetts. Along the way, at Lexington, shots were fired and several colonists were killed. Afterwards, colonists sniped at and harried the British on their return to Boston. In the wake of Lexington and Concord, American militia gathered around Boston, surrounding its British garrison. Nearly two months after the outbreak of hostilities, the Americans seized and fortified the strategic Charlestown Peninsula overlooking Boston harbour. In response, the British stormed the position in what became known as the battle of Bunker Hill: the first major battle of the American Revolution. At the end of the day, the British held the field, but at the cost of nearly a quarter of their army in Boston.