Rous made a major contribution to the game by rewriting the Laws of the Game in 1938, making them simpler and easier to understand. He was also the first to employ the diagonal system of control for referees as a standard practice. According to Belgian referee John Langenus, who had been in charge of the 1930 FIFA World Cup Final, he had seen referees from his country making a similar attempt at scientific positioning on the field of play.