The Thirteenth Amendment to the U.S. Constitution legally ended slavery in the United States. It was passed by Congress and ratifi ed by the required three-fourths of the states in 1865. President Abraham Lincoln had issued the Emancipation Proclamation in 1862, declaring slaves in areas in rebellion against the government to be freed by executive decree. Afterward, Lincoln and many of his fellow Republicans had believed that more permanent legislation in the form of a constitutional amendment prohibiting slavery would be needed to ensure that the Emancipation Proclamation could not be subsequently ruled either unconstitutional or a temporary war measure. The Thirteenth Amendment was the fi rst constitutional amendment to be adopted in more than sixty years, and it initiated a series of subsequent amendments, including the Fourteenth and Fifteenth Amendments, with which it is often associated. Those two Reconstruction-era amendments guaranteed citizenship and voting rights to African Americans and, along with the Thirteenth Amendment, represented a crucial step in the broadening of the American legal defi nitions and conceptions of freedom and equality.