With its spread to Persia, this game developed into Shāh Māt, or "the king is dead," which is where the modern word "checkmate" originates. The rules and pieces of the game changed signlatest rummy appificantly as it made its way from the Islamic world into Europe. By the 15th century, the game had evolved into what it is today, with the addition of the strong queen and the two-square pawn opening move, which significantly quickened play. The growth of trade routes and the migration of peoples had an impact on the spread of chess in addition to cultural exchange.