NEW YORK, NY.- Archaeologists working at Red Bank Battlefield, a site along the Delaware River south of Philadelphia, have uncovered the remains of 13 Hessian mercenaries who were killed during a bloody Revolutionary War battle.

The remains were found in a former trench that was part of the defenses of Fort Mercer, where 500 American patriots were stationed to prevent British ships from supplying troops in the city. On Oct. 22, 1777, a contingent of 2,000 Hessian soldiers fighting for the British set out to overwhelm the small force, but the day ended in a resounding defeat, with 377 Hessians killed but only 14 American casualties.

“Finding bone, finding Hessians was not on my radar,” said Jennifer Janofsky, a historian at Rowan University in Glassboro, New Jersey, and the director of Red Bank Battlefield Park. “We have documentation from that period showing where mass graves are. This was not on the map.”

Genetic studies are being conducted on the remains, which include isolated body parts. The hope is to eventually connect these to the names of soldiers known to have been killed in the battle and cast a finer light on life and death during the Revolutionary War.

Some of the bones display wounds from musket balls and from grapeshot that would have been fired from cannons inside the fort or from ships in the river. “These guys were being hit by all kinds of things,” said Wade Catts, principal archaeologist for South River Heritage Consulting in Newark, Delaware, who led the scientific fieldwork. “What a horrible place this would have been.”

Catts said he believed that the Hessian remains belonged to members of the Regiment von Mirbach, which is known to have attacked the center of Fort Mercer’s defenses. He was excited by an additional discovery: a British gold coin, worth about one month’s salary for the average soldier, that may have belonged to Lt. Col. Ernst Rudolf von Schieck, who commanded the Hessian regiment and died in the fighting.

“This is really an opportunity to expand our knowledge of the Hessian forces — about their material culture, about the men themselves,” Catts said.

The American soldiers defending the fort were from the 1st and 2nd Rhode Island Regiments and the 6th Virginia Regiment, and included a small number of New Jersey militiamen. The Rhode Island regiments were among the nation’s first integrated military units. Ten to 15% of the force was made up of Black soldiers and members of the Narragansett Indian Tribe. The fort was further supported by 13 ships of the Pennsylvania navy, with cannons that fired chain and bar shot — typically used to damage a ship’s sails — at the Hessian attackers.

For Janofsky, the human remains add poignancy to the story of the battle. Among the dead was a man between the ages of 17 and 19, the same age as many of her history students. “Very few of us have seen the violence of the battlefield, and it’s what we’ve been looking at for the past months,” she said. “I feel like we are charged with helping our visitors understand that moment.”

This article originally appeared in The New York Times.