Final answer:
Bartolomé de las Casas became an outspoken critic of the encomienda system and worked to protect Native Americans from the brutality of Spanish colonization and its associated diseases, leading to the New Laws of 1542 designed to improve conditions for the indigenous population.
Step-by-step explanation:
Spanish monks Bartolomé de las Casas and others responded to the devastation caused by Eurasian diseases in the Americas by advocating for the rights and humanity of Native Americans. Bartolomé de las Casas, after witnessing the harsh treatment and disease impact on the natives, became a vocal critic of the Spanish encomienda system.
His efforts led to the implementation of the New Laws of 1542, which sought to protect the indigenous people by limiting the encomienda system, though they faced resistance from Spanish settlers in the Americas.
De las Casas's engagement with the Spanish monarchy and advocacy represented a significant humanitarian step towards recognizing and attempting to alleviate the suffering caused by colonization and introduced diseases.