He proposed to replace the slave labor of the natives with the importation of slaves from Africa, to keep the natives free. He eventually recanted this stance as well, and became an advocate for the Africans in the colonies. Las Casa wanted the colonists to bring Africans to labor as slaves in New Spain because they would provide cheap labor.
Charles Dickens used his talent as a writer to bring attention to the horrors of child labor from his novel, 'Oliver Twist.'. He was not alone, several groups of advocates relentlessly lobbied for child labor laws. However, Dickens was one of most well known and popular celebrities of his day, and lending his voice certainly helped to bring about child labor and protection laws.