This Day in American Military History

11 September 1777: The Battle of Brandywine began—the most significant engagement of the American Revolution. British troops, led by General William Howe, marched on Philadelphia; Continental forces led by General George Washington tried to stop them at the Brandywine River near Chadds Ford, Pennsylvania. The Americans were defeated, and the British went on to take Philadelphia two weeks later. Washington’s men began their long and insufferable winter encampment at Valley Forge, Pennsylvania.

Brandus, Paul. This Day in U.S. Military History (p. 221). Bernan Press. Kindle Edition.