The question of whether slaves should be counted for purposes of representation in the House of Representatives and for taxation was a significant issue during the drafting of the U.S. Constitution. This debate was addressed in the Three-Fifths Compromise, which was reached at the Constitutional Convention in 1787.
Under this compromise, slaves were counted as three-fifths of a person for both representation and taxation purposes. This arrangement allowed Southern states, which had large populations of enslaved individuals, to gain more representation in Congress than they would have had if only free individuals were counted, while also allowing for some tax assessments based on the slave population.
The Three-Fifths Compromise was a controversial and pivotal aspect of the Constitution, reflecting the broader conflicts between free and slave states. It remained in effect until the post-Civil War amendments (specifically the 14th Amendment in 1868), which established that all persons are to be counted equally for representation and taxation.
In summary, according to the Three-Fifths Compromise, slaves were counted as three-fifths of a person for both representation in the House of Representatives and for taxation purposes.