Both meetings were called in reaction to British Parliament’s attempts to assert its control in the American colonies. When colonial delegates to the First Continental Congress met, they developed a plan but were obviously prepared for it not to work, since even before dismissal they agreed to reconvene if it were necessary to do so. In short, the first Congress developed Plan A; the second resorted to Plan B (which was one last appeal to the king) and then to Plan C (finally declaring independence from Britain).

The First Continental Congress convened on September 5, 1774, in Philadelphia, Pennsylvania. The meeting was largely a reaction to the so-called Intolerable Acts (or the Coercive Acts), which British Parliament had passed in an effort to control Massachusetts after the rebellion of the Boston Tea Party (December 1773). Sentiment grew among the colonists that they would need to band together in order to challenge British authority. Soon 12 colonies dispatched 56 delegates to a meeting in Philadelphia. (The thirteenth colony, Georgia, declined to send representatives but agreed to go along with whatever plan was developed.) Delegates included Samuel Adams (1722–1803), George Washington (1732–1799), Patrick Henry (1736–1799), John Adams (1735–1826), and John Jay (1745–1829). Each colony had one vote, and when the meeting ended on October 26, the outcome was this: The Congress petitioned the king, declaring that the British parliament had no authority over the American colonies, that each colony could regulate its own affairs, and that the colonies would not trade with Britain until Parliament rescinded its trade and taxation policies. The petition stopped short of proclaiming independence from Great Britain, but the delegates agreed to meet again the following May—if necessary.

But King George III (1738–1820) was determined that the British Empire be preserved at all costs; he believed that if the empire lost the American colonies, then there may be a domino effect, with other British possessions encouraged to also demand independence. He feared these losses would render Great Britain a minor state, rather than the power it was. Britain unwilling to lose control in America, in April 1775 fighting broke out between the redcoats and patriots at Lexington and Concord, Massachusetts. So, as agreed, the colonies again sent representatives to Philadelphia, convening the Second Continental Congress on May 10. Delegates—including George Washington, John Hancock (1737–1793), Thomas Jefferson (1743–1826), and Benjamin Franklin (1706–1790)—organized and prepared for the fight, creating the Continental army and naming Washington as its commander in chief. With armed conflict already under way, the Congress nevertheless moved slowly toward proclaiming independence from Britain: On July 10, two days after issuing a declaration to take up arms, Congress made another appeal to King George III, hoping to settle the matter without further conflict. The attempt failed, and the following summer the Second Continental Congress approved the Declaration of Independence, breaking off all ties with the mother country.