September 1774: Continental Congress representing the thirteen colonies meets in Philadelphia, Pennsylvania, to define America 's rights and to limit the British Parliament's power over the colonies. The Congress schedules a second meeting for May 1775.

April 18, 1775 : Aware that Massachusetts militia members are being trained for immediate military service and that ammunition is being stockpiled, a British force of around seven hundred men sets out from Boston to seize munitions gathered at Concord (less than twenty miles from Boston ). The American Committee of Safety (including Paul Revere) warns militia members that the British are coming. On April 19, the British force kills eight Americans in a battle at Lexington, Massachusetts, then proceeds toward Concord. Americans fight surprisingly well at Concord against a superior force; the British return to Boston with 273 casualties, while Americans suffer less than 100. Militia companies and then the...