When Hiram Rhodes Revels traveled to Washington in 1870, he brought a historic piece of paper with him: a handwritten document certifying his right to serve in the United States Senate. Revels was poised to become the first Black person to serve in Congress.

But despite his election to the post, the senator-to-be wasn’t welcomed to the legislature. Instead, the United States-born politician faced stiff debate from future colleagues over whether he was a citizen.