[Robert LeRoy Parker, alias Butch Cassidy, head-and-shoulders portrait]

Butch Cassidy (1866–1908) American outlaw and foremost member of the Wild Bunch, a collection of bank and train robbers who ranged through the western United States in the 1880s and ’90s. Robert Parker took his alias from Mike Cassidy, an older outlaw from whom he learned cattle rustling and gunslinging (1884–87). Thereafter—except for two years of chiefly cowboying (1891–92) and two years (1894–96) in Wyoming State Prison—he was teamed up with a succession of outlaws. His favourite friend and confederate was Elzy Lay, with whom, alone or in a gang, he helped rob a number of trains, banks, and paymasters and rustled horses and, less often, cattle.