Following its ratification by the necessary three-quarters of U.S.
states, the 14th Amendment, granting citizenship to all persons
born or naturalized in the United States—including formerly
enslaved people—is officially adopted into the U.S. Constitution

Secretary of State William Seward (below) issued a proclamation certifying the amendment. 

William Henry Seward
(May 16, 1801 – October 10, 1872)

President Jimmy Carter (above) signed a bill that restored full U.S.
citizenship rights to Confederate President Jefferson Davis.

Jefferson Finis Davis (June 3, 1808 – December 6, 1889)