Which event is commonly referred to as the start of the American Revolution?

The Battles of Lexington and Concord are often recognized as the initial armed conflicts of the American Revolution, marking a pivotal moment where tensions between the American colonies and British troops erupted into open warfare. These skirmishes, which took place on April 19, 1775, demonstrated the colonists' willingness to take up arms in defense of their rights and liberties against perceived oppression. The battles symbolized a significant shift from peaceful protest to active resistance, effectively igniting the revolutionary spirit among the colonies and leading to further conflict and ultimately, the quest for independence.

The other events, while important in the context of the Revolution, occurred later or represented different aspects of colonial resistance. The Boston Massacre took place in 1770 and is often viewed as a catalyst for outrage against British rule, while the Boston Tea Party in 1773 was a direct protest against taxation without representation. The signing of the Declaration of Independence in 1776 formalized the colonies' break from Britain but happened after the battles had already established the conflict as a war. Thus, the Battles of Lexington and Concord uniquely stand as the true beginning of military engagement in the American Revolution.