By day, John Pierre Burr worked as a barber. By night, he was a conductor on the Underground Railroad, working with individuals such as Harriet Tubman and Lucretia Mott to transport runaways to Canada. A new headstone unveiled over the weekend at Philadelphia’s Eden Cemetery honors his life accomplishments, and also shares something new: John Pierre, the updated epitaph reads, was the “Son of Vice-President Aaron Burr and Mary Eugenie Emmons.”

As Hannah Natanson reports for the Washington Post, that change comes thanks to Sherri Burr, a law professor at the University of New Mexico. The professor spent years delving into her forefather’s parentage, and last September, she presented her findings to the Aaron Burr Association. The group, which includes fellow descendants and history lovers, unanimously recognized John Pierre and his sister Louisa Charlotte as the children of founding father Aaron Burr. Their mother, Mary Eugenie Emmons, hailed from Calcutta, India, and worked as a servant in the Burr household.

Speaking with NPR’s Michael Martin, Sherri says she discovered the ancestral connection while working on a book titled Complicated Lives: Free Blacks in Virginia, 1619-1865.

“After I finished researching my father's maternal line, I decided to look at my family's paternal name, which had always been a secret from my brother and me,” the author explains. “We were told that there was something special about our family name, but we were never told what it was.”