Final answer:
The American Revolution began with the confrontations at Lexington and Concord on April 19, 1775, after a buildup of colonial resentment towards British taxation and legislation without representation. This marked the commencement of open hostilities, signaling the start of the war.
Step-by-step explanation:
The American Revolution began in earnest with the confrontations at Lexington and Concord on April 19, 1775. After a series of increasingly contentious acts by the British government, including the imposition of taxes without colonial representation and the enforcement of the Intolerable Acts, tensions escalated into armed conflict. These skirmishes marked the outbreak of hostilities between the American colonists and British forces, effectively starting the revolutionary war. While the Stamp Act and the Boston Tea Party were critical events leading to the revolution, it was the open armed conflict at Lexington and Concord that signified the point of no return, making it the definitive beginning of the American Revolution.
After the French and Indian War, known in Europe as the Seven Years' War, the British government sought to recover war debts by taxing the colonies and asserting stricter control. Resentment towards these measures grew as the colonists developed a reinforced sense of autonomy and rights under the British constitution. Events like the First Continental Congress drafting a statement of American rights, and the publication of Thomas Paine's 'Common Sense' rallied American sentiments towards independence from Britain, culminating in the armed clashes in Massachusetts.