British Troops March Into Philadelphia
On September 26, 1777, British troops marched into Philadelphia and occupied the city forcing the Continental Congress, meeting in the Pennsylvania State House (later renamed Independence Hall), to flee to the interior of Pennsylvania.
General Washington and his army had battled the British south of Philadelphia at Brandywine Creek on September 11. That evening, Washington sent a letter to the Continental Congress reporting the outcome.
Washington's attempts to hold the British outside of Philadelphia failed. While the British occupied the city, Washington and his army took up winter quarters at Valley Forge. Supplies and morale were low as the troops braved the snow and near starvation. The soldiers of the War for Independence endured bleak times at Valley Forge.
Here in the winter of discontent, our fortunes sank to the lowest point. But from this place, Washington went forth conquering, and to conquer, and to become the foremost man of all the world.”— "At Valley Forge," speech by Speaker of the House Champ Clark
In 1777, as part of a grand strategy to end the war, the British sent an invasion force from Canada to seal off New England, which the British perceived as the primary source of agitators. In a major case of mis-coordination, the British army in New York City went to Philadelphia which it captured from Washington. The invasion army under Burgoyne waited in vain for reinforcements from New York, and became trapped upstate. It surrendered after the Battle of Saratoga, New York, in October 1777. From early October 1777 until November 15 a pivotal siege at Fort Mifflin, Philadelphia, Pennsylvania distracted British troops and allowed Washington time to preserve the Continental Army by safely leading his troops to harsh winter quarters at Valley Forge.