town and taking as prisoners those inside the makeshift hospital of St. Andrew's Church, only to be later repelled back to New Jersey, releasing the prisoners and causing numerous British casualties in the process. There are rumors that Mercer exclusively originated Washington's plan to cross the Delaware River and surprise the Hessians at the Battle of Trenton on December 26, 1776, and Mercer was certainly a major contributor to its execution. The victory at Trenton (and a small monetary bonus) made Washington's men agree to a ten-day extension to their enlistment. When Washington decided to face off with Cornwallis during the Second Battle of Trenton on January 2, 1777, Mercer was given a major role in the defense of the city. The next day, January 3, 1777, Washington's army was en route to Princeton, New Jersey. While leading a vanguard of 350 soldiers, Mercer's brigade encountered two British regiments and a mounted unit. A fight broke out at an orchard grove and Mercer's horse was shot from under him. Getting to his feet, he was quickly surrounded by British troops who mistook him for George Washington and ordered him to surrender. Outnumbered, he drew his saber and began an unequal contest. He was finally beaten to the ground, bayoneted repeatedly (seven times), and left for dead. When he learned of the British attack and saw some of Mercer's men in retreat, Washington himself entered the fray. Washington rallied Mercer's men and pushed back the British regiments, but Mercer had been left on the field to die with multiple bayonet wounds to his body and blows to his head. Legend has it that a beaten Mercer, with a bayonet still impaled in him, did not want to leave his men and the battle and was given a place to rest on a white oak tree's trunk, and those who remained with him stood their ground. The tree became known as "the Mercer Oak" and is the key element of the seal of Mercer County, New Jersey. When he was discovered, Mercer was carried to the field hospital in the Thomas Clarke House (now a museum) at the eastern end of the battlefield. Benjamin Rush cared for Mercer and other wounded troops. Rush was assisted in caring for the wounded by Quakers. Local Quakers continued to care for wounded troops from both Continental and British forces, after the Continental Army moved North.