Fighting broke out at other places along the road as the British soldiers in their bright red uniforms made their way back to Boston. More than 250 "redcoats" were killed or wounded. The Americans lost 93 men.

Deadly clashes continued around Boston as colonial representatives hurried to Philadelphia to discuss the situation. A majority voted to go to war against Britain. They agreed to combine colonial militias into a continental army, and they appointed George Washington of Virginia as commander-in-chief. At the same time, however, this Second Continental Congress adopted a peace resolution urging King George III to prevent further hostilities. The king rejected it and on August 23 declared that the American colonies were in rebellion.

Calls for independence intensified in the coming months. Radical political theorist Thomas Paine helped crystallize the argument for separation. In a pamphlet called Common Sense, which sold 100,000 copies, he attacked the idea of a hereditary monarchy. Paine presented two alternatives for America: continued submission under a tyrannical king and outworn system of government, or liberty and happiness as a self-sufficient, independent republic.

The Second Continental Congress appointed a committee, headed by Thomas Jefferson of Virginia, to prepare a document outlining the colonies' grievances against the king and explaining their decision to break away. This Declaration of Independence was adopted on July 4, 1776. The 4th of July has since been celebrated as America's Independence Day.

Liberty Bell, in Philadelphia, Pennsylvania, an enduring symbol of American freedom. It was first rung on July 8, 1776, to celebrate the adoption of the Declaration of Independence. (Interior Department/National Park Service)

The Declaration of Independence not only announced the birth of a new nation. It also set forth a philosophy of human freedom that would become a dynamic force throughout the world. It drew upon French and British political ideas, especially those of John Locke in his Second Treatise on Government, reaffirming the belief that political rights are basic human rights and are thus universal.

Declaring independence did not make Americans free. British forces routed continental troops in New York, from Long Island to New York City. They defeated the Americans at Brandywine, Pennsylvania, and occupied Philadelphia, forcing the Continental Congress to flee. American forces were victorious at Saratoga, New York, and at Trenton and Princeton in New Jersey. Yet George Washington continually struggled to get the men and materials he desperately needed.

Decisive help came in 1778 when France recognized the United States and signed a bilateral defense treaty. Support from the French government, however, was based on geopolitical, not ideological, reasons. France wanted to weaken the power of Britain, its long-time adversary.

The fighting that began at Lexington, Massachusetts, continued for eight years across a large portion of the continent. Battles were fought from Montreal, Canada, in the north to Savannah, Georgia, in the south. A huge British army surrendered at Yorktown, Virginia, in 1781, yet the war dragged on with inconclusive results for another two years. A peace treaty was finally signed in Paris on April 15, 1783.

The Revolution had a significance far beyond North America. It attracted the attention of Europe's political theorists and strengthened the concept of natural rights throughout the Western world. It attracted notables such as Thaddeus Kosciusko, Friedrich von Steuben, and the Marquis de Lafayette, who joined the revolution and hoped to transfer its liberal ideas to their own countries.

The Treaty of Paris acknowledged the independence, freedom, and sovereignty of the 13 former American colonies, now states. The task of knitting them together into a new nation lay ahead.