Answer:
The Black Death, I looked it up and this seems to be the right answer
Explanation:
<span>On September 11, 1777 British General William Howe's army defeated George Washington's army defending Philadelphia at the Battle of Brandywine. Washington and his army were forced to retreat, there was no longer an American army defending Philadelphia. The British marched in and occupied Philadelphia...until the fortunes of war changed and the British left Philadelphia in June, 1778 without a fight.</span>