Final answer:
General Howe's British forces captured Philadelphia on the same day that Washington learned of Lee's capture, defeating American troops in the Battle of Brandywine Creek and forcing the Continental Congress to flee.
Step-by-step explanation:
The event that coincided with General Howe's occupation of Philadelphia on the same day as Washington's knowledge of Lee's capture was a momentous one in the American history during the American Revolution. In August 1777, Howe brought fifteen thousand British troops to Chesapeake Bay and subsequently defeated Washington's soldiers in the Battle of Brandywine Creek. This victory allowed British forces to take control of Philadelphia, which was the meeting place of the Continental Congress, forcing its members to flee. The British then occupied the city during the winter of 1777-1778, while Washington's army camped at Valley Forge, Pennsylvania. The capture of Philadelphia was a significant British achievement, impacting the American strategy and necessitating a harsh winter encampment for Washington's troops. The strategic importance of Philadelphia and its eventual occupancy by British troops contributed to the overall narrative of the British and American victories within the war.