Excerpts from Books and Wikipedia
"But by far the greatest religious champion of the indigenous people was Bartolomé de las Casas, prototype for a long line of radical priests in Latin America. las Casas was a university-educated, fortune-seeking young gentleman—no radical at all—when he came to America in 1502. He got an encomienda himself and for twelve years lived the life of an early Caribbean conqueror, watching indigenous people die by the dozen from exploitation and disease. He was about forty when, in 1514, he had a change of heart, influenced, apparently, by the fiery sermons of a member of the Dominican order who had begun to preach against Spanish exploitation of encomiendas. By 1515, las Casas, now a Dominican himself, returned to Spain and proposed various ways to protect indigenous Americans from the encomienda system. . . . In 1537, the pope issued a proclamation, partly inspired by las Casas, saying that the indigenous people were exactly that: people, not subhuman beings, as some claimed. In 1542, largely thanks to las Casas, the Spanish Crown issued the famous New Laws of the Indies for the Good Treatment and Preservation of the Indians . . . Eventually ending encomiendas altogether."