On 19 April 1775, British soldiers were sent to seize an illegal depot of arms in the nearby town of Concord. At the village of Lexington, they confronted 70 militiamen (armed farmers) and the American War of Independence began. The colonists knew that, if they were to succeed in the struggle, some kind of union would be necessary. In May 1775, The Second Continental Congress met in Philadelphia and began to assume the functions of a national government and established the American Continental Army. The Virginian landowner, George Washington was placed in command.
In this stage there were some radicals who demanded complete independence, but the majority of the Congress still believed in the possible compromise with the King of England. The idea of independence became extremely popular after the publication of Thomas Paine's Common Sense in 1776. In this pamphlet he argued that independence was the only remedy, and that it would be harder to win the longer it was delayed. The idea of independence became universal soon. On 4 July, 1776, the Continental Congress adopted the Declaration of Independence declaring that the colonies are and of right ought to be free and independent States. The author of this document was Thomas Jefferson.
In the first years, the war went badly for the Americans. It was very difficult to convert colonists into an efficient fighting force since American soldiers were short of money and supplies, and they lacked training and discipline. The quality of the officers was poor, and they had practically no navy. The English, on the other hand, had to fight 3,000 miles from home. It was expensive to transport men and supplies. Also proper strategic management of the force from London was impossible. The British captured New York City in 1776, and Philadelphia was captured a year later. The tide turned in October 1777 at Saratoga, where Continentals forced the British to surrender. It was a turning point in the war. After this victory, a Franco-American alliance was signed in February 1778. This alliance brought men, money, encouragement, supplies and, above all, the navy. Holland and Spain also began to support Americans soon.
After 1778, the fighting shifted to the south. The Americans suffered many defeats here, but they won the last battle, which was decisive. At Yorktown, Virginia, in 1781, the English commander, Lord Cornwallis was forced to surrender by the American army under George Washington's command. The war was now over, but King George III refused to acknowledge defeat for another two years. The Treaty of Paris was signed in September 1783. The treaty recognized the independence of the United States and granted the new nation all the territory north of Florida, south of Canada and east of the Mississippi River.