ABOLITIONThere had always been objections to slavery throughout history. However, they rarely came to anything because double standards were involved, as all those in power were all directly, or indirectly, financially involved in he trade.
The realAbolition movement started in North America with the Baptists in Carolina and the Presbyterians in Pennsylvania state . The first example was the condemning of the Witches of Salem. They were in fact all the slave traders.
The Quakers of Newport, Massachusetts and Rhode Island state , all of whom were large slave owners, also began the realisation of the inconsistency of slavery with Christian principles.
But there was another reason in North Americabeyond philanthropy and that was the fear of rebellion. There was instant pressure to reduce the number of slaves coming in because of this.
This was the period of the Enlightenment. The great wave of ideas and emotions of which Voltaire was the grand figure who wrote in 1764:
"People who traffic in their own children are more condemnable than the buyer." condemning both the African and the Slaves.
Together with the American beginnings, the movement finally took off in the Atlantic