Bartolome de las Casas was a Spanish priest, later a Dominican friar, who denounced the encomienda system of Native American slave labor embraced by the conquistadores. For the rest of his life, he fought for the rights of indigenous Americans, often speaking directly to the King of Spain.
In 1502, the young priest visited his family's holdings on Hispaniola, traveling throughout the island. He was horrified at the Spanish treatment of the natives, who were enslaved, brutalized and sometimes slaughtered. In 1514, he renounced all his family's wealth earned through native slave labor, denounced the encomienda plantation system as sinful and began to work to free the indigenous people.
While he saw some initial success, the death of King Ferdinand in 1516 threw all his plans into chaos. Later successes in Guatemala were undone when natives who had been pacified and somewhat Christianized were enslaved by greedy Spanish settlers. In 1542, he convinced King Charles V to alter the encomienda system with the New Laws, but these were rarely enforced in Spanish colonies. With his life in danger from angry plantation owners, he returned to Spain to write about his experiences with the Indians. His books, including "Historia de las Indias," helped alter Spanish sentiment toward the natives and preserved for posterity the harsh tactics of the conquistadores.