Bartolomé de las Casas (US: /lɑːs ˈkɑːsəs/ lahs KAH-səs, Spanish: [baɾtoloˈme ðe las ˈkasas] (About this soundlisten); c. 1484 – 18 July 1566) was a 16th-century Spanish colonist who acted as a historian and social reformer before becoming a Dominican friar.