[1] In December 1776, as his army retreated across New Jersey under British pressure, George Washington appealed to the Continental Congress for more soldiers.

The delegates gave Washington sweeping authority to appoint officers and recruit an additional 16 battalions of infantry, three regiments of artillery, an engineer corps, and light cavalry formations.

[2] Upon the recommendation of delegate Richard Henry Lee, Washington appointed Thomas Hartley as colonel of one "additional" regiment.

[7] On 11 September 1777, Hartley's Regiment fought at the Battle of Brandywine as part of a 2,000-man division led by Brigadier General Anthony Wayne.

The right-most unit was deployed on the Great Road with Colonel Thomas Proctor's artillery lunette about 200 yards (183 m) in front.

The Anglo-Hessian division led by Lieutenant General Wilhelm von Knyphausen attacked across Brandywine Creek at Chadds Ford.

Shortly after mounting a second horse, he was fatally struck by a projectile and fell into the arms of Lieutenant Colonel Adam Hubley of the 10th Pennsylvania.

When the British and Hessians threatened to turn both of Wayne's flanks, he withdrew his division 600 yards (549 m) to a hill while successfully bringing off the brigade artillery.

Hubley admitted that 52 Americans died and total casualties numbered about 300 men, while the British lost only three killed and eight wounded.

After the light troops held up Conway's advance near Mount Pleasant, Sullivan committed the 1st and 2nd Maryland Brigades to the right of the Germantown Road and Wayne's division to the left.

[13] By this time the British Army commander Sir William Howe appeared on the scene and attempted to rally his men.

After firing a few volleys at the house with no effect, Wayne's men left it behind and continued their southward advance into the morning's fog.

When the American rear echelon units began bombarding the Chew House with cannons, Wayne and his men became anxious and turned back.

Confused in the fog and taking fire from several directions, Wayne's men took to their heels and did not rally until they were 3 miles (4.8 km) from the battlefield.

In September 1778, elements of the regiment participated in a counter-raid in which they destroyed a few indigenous villages, recovered plunder taken in the Wyoming Valley, and skirmished with Seneca warriors.

[22] In this action, Butler's Rangers, Brant's Volunteers, and several hundred Seneca and Cayuga warriors attempted to ambush Sullivan's 3,200-man column.

The Iroquois people were forced to beg for food from the British that winter, but their ferocious attacks on frontier settlements continued.