Baseball's peak popularity in Britain was in the years immediately preceding World War II. Professional baseball teams often shared grounds with football clubs and the game was run at a professional standard with up to 10,000 spectators per game. In 1933, in response to a challenge from Major League Baseball’s National League President, John Haydler, the wealthy British gambling tycoon, Sir John Moores, established the National Baseball Association and continued to fund the establishment of amateur and professional leagues in England.