In 1777, the Vermont Republic, which was however unrecognized by the United States, handed a condition constitution prohibiting slavery. The Pennsylvania Abolition Society, led in component by Benjamin Franklin, was started in 1775, and Pennsylvania started gradual abolition in 1780. In 1783, the Supreme Judicial Court of Massachusetts ruled in Commonwealth v. Jennison that slavery was unconstitutional beneath the state's new 1780 constitution.