William H. Bonney (born William Henry McCarty, Jr. c.1859-1861[2] – July 14, 1881), better known as Billy the Kid and also known as William Antrim, was a 19th-century gunman who participated in the Lincoln County War and became a frontier outlaw in the American Old West. According to legend, he killed twenty-one men,[3] but it is generally believed that he killed eight.[3] He killed his first man on August 17, 1877,[4] at around 17 years old.