This time line is drawn largely from the work of Richard B. Morris, in particular his Encyclopedia of American History.
1777-1778
1777
Battle of Princeton. British General Howe reacted to the Battle of Trenton by sending a large force of men to New Jersey. At Princeton, Washington once again launched a surprise attack, and succeeded in defeating the British. His efforts cleared most of New Jersey of enemy forces, and greatly boosted American morale.
America Has a Flag. On June 14, Congress declared that the flag of the United States would consist of thirteen alternating red and white stripes, and a blue field with thirteen white stars.
The British Attack Philadelphia. British and Americans met at Brandywine Creek, Pennsylvania. The Americans retreated, and the British soon occupied Philadelphia, forcing Congress once again to flee the city. After retreating further during the Battle of Germantown, Washington settled his army for the winter in Valley Forge -- a winter of extreme cold and great hunger.
Saratoga. On October 7, British and American troops engaged in New York. Fatigued from battle and short of supplies, British General John Burgoyne's troops were repulsed by American forces under General Horatio Gates. On October 8, Burgoyne retreated to Saratoga; by October 13th, he asked for terms of surrender. The "Convention of Saratoga" called for Burgoyne's army to be sent back to England, and for each soldier to pledge not to serve again in the war against the colonies.
The "Conway Cabal." Many in Congress were unhappy with Washington's leadership; some murmured the name of General Horatio Gates as a possible replacement. Thomas Conway, the army's inspector general, wrote a critical letter to Gates about Washington, leading many to believe there was an organized effort to replace Washington. Conway resigned from the army, and eventually apologized to Washington.
Articles of Confederation. When Richard Henry Lee made a motion for independence (1776), he also proposed a formal plan of union among the states. After a discussion lasting more than a year, the Articles of Confederation were adopted by Congress, although the states did not ratify the Articles until 1781.
1778
France and America Become Allies. France and America formed an alliance, negotiated by Benjamin Franklin, stating that each would consider the other a "most favored nation" for trade and friendship; France would be obligated to fight for American independence; and America would be obligated to stand by France if war should occur between France and Great Britain. Within four months, France and Great Britain were at war.
The British Attempt to Make Peace. Threatened by the alliance between France and America, Parliament proposed the repeal of the Tea Act (1773) and Coercive Acts (1774), pledged not to tax the colonies, and sent peace commissioners to America. However, most Americans were interested only in British recognition of American independence. When a British commissioner tried to bribe congressmen Joseph Reed, Robert Morris, and Francis Dana, Americans became even less interested in reconciliation. Competing for support from the American people, both Congress and the desperate commissioners appealed directly to them with broadsides, but the British commissioners soon returned to Great Britain, their mission a failure.
John Paul Jones Wins Victories. Although Esek Hopkins was never very successful with the American navy, Captain John Paul Jones won several victories against the British with his ship, the "Ranger."
The Battle of Monmouth. When the British headed for New York, Washington left Valley Forge to follow. At the Battle of Monmouth, American General Charles Lee gave several confused orders, and then ordered a sudden retreat. Washington's arrival on the scene saved the battle, although the British escaped to New York during the night. Lee was later court-martialed.