Final answer:
Bartolomé de Las Casas exposed the brutal treatment of Native Americans and the atrocities committed by Spanish conquistadors in his letters, which led to the creation of the New Laws of 1542, although they were met with resistance and failed to completely abolish the encomienda system.
Step-by-step explanation:
Bartolomé de Las Casas's Exposures in His Letters
Bartolomé de Las Casas, in his letters to the Council of Indies in Madrid, exposed the harsh realities and brutal treatment of Native Americans by the Spanish conquistadors in the New World. His most influential work, A Short Account of the Destruction of the Indies, vividly details the atrocities committed against indigenous peoples, describing the conquerors as 'ravening wolves' tearing Native Americans 'to shreds' and inflicting 'untold misery, suffering, and distress.' His relentless advocacy was instrumental in the creation of the New Laws of 1542, which aimed to reform the encomienda system though met with great resistance in the Americas.
De Las Casas began as an encomendero himself but underwent a moral transformation that led him to become an advocate for the rights of indigenous peoples. His accounts contributed to the humanitarian arguments used by other European powers to challenge Spain's colonial practices. Despite his efforts and the official issuance of the New Laws, the encomienda system persisted due to the violent opposition from Spanish settlers in the colonies.