President Joe Biden’s great-great-grandfather was pardoned by former President Abraham Lincoln, according to U.S. National Archives records.

Historian David J. Gerleman explained in The Washington Post that the historic documents are “the hidden link between the two men — and between two presidents across the centuries.”

Gerleman wrote that the “slender sheaf of 22 well-preserved pages of his trial transcript, unobtrusively squeezed among many hundreds of other routine court-martial cases in the National Archives,” shares a “story that has waited 160 years to be told.”

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The story that links Lincoln and Biden

Axios reported that Biden’s great-great-grandfather had engaged in a Civil War-era brawl that “saw him charged with attempted murder.”

These documents reportedly reveal that Biden’s ancestor, Moses J. Robinette, got into a fight with a Union Army civilian employee as they were camped near Beverly Ford, Virginia, along the Rappahannock River on March 12, 1864.

The other man involved in the fight, John J. Alexander, bled from “knife wounds” and Robinette ended up being charged with attempted murder and was incarcerated near Florida, according to Fox News.

The fight was reportedly a result of Alexander rushing at Robinette after overhearing Robinette saying something about him to a cook.

CBS News reported that Robinette said he thought that Alexander “possibly might have injured me seriously had I not resorted to the means I did.”

The charges against Robinette stated that he was “intoxicated and had incited a dangerous quarrel,” and deemed that since a weapon was involved, there was an intent to kill on Robinette’s part, according to USA Today.

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Why did Lincoln pardon Biden’s great-great-grandfather?

Fox News reported that three of Robinette’s friends who were officers in the U.S. Army petitioned Lincoln directly to overturn Robinette’s sentence.

Robinette reportedly wrote a letter in an attempt to “overturn the conviction” with John S. Burdett, David L. Smith and Samuel R. Steel arguing that Robinette’s sentence was excessive for a man “defending himself and cutting with a penknife a teamster much his superior in strength and size, all under the impulse of the excitement of the moment.”

The petition said that Robinette was “a true and faithful supporter of the Union” and had opposed “traitors and their schemes to destroy the government.”

Lincoln reportedly agreed with the request and wrote, “Pardon for unexecuted part of punishment. A. Lincoln. Sep. 1. 1864.”

“Those few pages not only fill an unknown piece of Biden family history, but also serve as a reminder of just how many Civil War stories have yet to be told,” Gerleman wrote.

Read the documents in full on DocumentCloud.