After the American Civil War, during a period in American history known as Reconstruction (1865–1877), Confederate soldiers had to take an oath of allegiance in order to be regain their American citizenship. This oath served as proof that they were willing to "protect and defend the constitution of the United States," to which President Lincoln had added the Thirteenth, Fourteenth, and Fifteenth Amendments, which declared a legal end to slavery, decreed that all people born or naturalized in America were US citizens, and declared that men from all races had the right to vote. Other Confederates who were pardoned or granted amnesty, first by President Lincoln and then by President Johnson, also had to take an oath of allegiance. It is said that President Johnson had issued 13,500 pardons by 1867.