Nine men's morris is a strategy board game for two players. It is an ancient game, dating back to at least the Roman Empire. The game is also known as nine-man morris, mill, mills, the mill game, merels, merrills, merelles, marelles, morelles, and ninepenny marl in English. In North America, the game has also been called cowboy checkers, and its board is sometimes printed on the back of checkerboards. Nine men's morris is a solved game, that is, a game whose optimal strategy has already been calculated. It has been shown that with perfect play from both players, the game results in a draw.