How did the action's of Bartolome de last casa lead to the start of African slavery in the Americad

Bartolomé de las Casas, worked tirelessly to prevent the enslavement of all native people and later regretted wholeheartedly his advocacy of African slavery. Indigenous and black activists and protestors for 500 years have taken up his arguments to push for changes to the systems that have made them second-class citizens.