The Three-Fifths Compromise dealt with slavery. When the writers of the Constitution were developing their ideas regarding the legislative branch, they decided to create a legislative branch with two houses. In one of the houses, the number of representatives would be based on the population of a state. This was the House of Representatives.
The issue was if slaves would be counted when determining a state’s population. The South wanted each state to count as one person. This would give the South more people and, therefore, more representatives. The North didn’t want slaves to count at all. Massachusetts supported this concept. The northern states said that since slaves had no rights and were legally viewed as property, they shouldn’t be counted at all.
In the Three-Fifths Compromise, five slaves counted as three people. Massachusetts supported this compromise. This compromise allowed the writers of the Constitution to move forward.