Congress passed the First and Second Reconstruction Acts in March 1867. Although the Constitution did not grant suffrage to African American men until ratification of the Fifteenth Amendment in 1870, the Reconstruction Acts of 1867 enfranchised black males at the state level. Congress charged the Freedmen’s Bureau with supervising elections in the Southern states, including voter registration.
Records of the Bureau of Refugees, Freedmen and Abandoned Lands, National Archives and Records Administration
Such measures will be taken as will inform all Freedmen entitled to be registered….that, as they will not be allowed to suffer from the honest exercise of the right of suffrage, they should disregard all threats or undue influence tending to prevent or restrain the same.