Bartolomé de las Casas O.P. (c. 1484 – 18 July 1566) was a 16th-century Spanish historian, social reformer and Dominican friar. He became the first resident Bishop of Chiapas, and the first officially appointed "Protector of the Indians." His extensive writings, the most famous A Short Account of the Destruction of the Indies and Historia de Las Indias, chronicle the first decades of colonization of the West Indies and focus particularly on the atrocities committed by the colonizers against the Indigenous peoples.
Arriving as one of the first settlers in the New World he participated in, and was eventually compelled to oppose, the atrocities committed against the Native Americans by the Spanish colonists. In 1515 he reformed his views, gave up his Indian slaves and encomienda, and advocated, before King Charles V, Holy Roman Emperor, in behalf of rights for the natives. In 1522 he attempted to launch a new kind of peaceful colonialism on the coast of Venezuela, but this venture failed causing Las Casas to enter the Dominican Order and become a friar, leaving the public scene for a decade. He then traveled to Central America undertaking peaceful evangelization among the Maya of Guatemala and participated in debates among the Mexican churchmen about how best to bring the natives to the Christian faith. Traveling back to Spain to recruit more missionaries, he continued lobbying for the abolition of the encomienda, gaining an important victory by the passing of the New Laws in 1542. He was appointed Bishop of Chiapas, but served only for a short time before he was forced to return to Spain because of resistance to the New Laws by the encomenderos, and conflicts with Spanish settlers because of his pro-Indian policies and activist religious stances. The remainder of his life was spent at the Spanish court where he held great influence over Indies-related issues. In 1550 he participated in the Valladolid debate; he argued against Juan Ginés de Sepúlveda that the Indians were fully human and that forcefully subjugating them was unjustifiable. Sepúlveda countered that they were less than human and required Spanish masters in order to become civilized.
Bartolomé de las Casas spent 50 years of his life actively fighting slavery and the violent colonial abuse of indigenous peoples, especially by trying to convince the Spanish court to adopt a more humane policy of colonization. And although he failed to save the indigenous peoples of the Western Indies, his efforts resulted in several improvements in the legal status of the natives, and in an increased colonial focus on the ethics of colonialism. Las Casas is often seen as one of the first advocates for universal Human Rights.