In Major League history, there have been twenty-one World Series sweeps. Thirteen Fall Classics have been won or swept by the American League. The National League has won eight Series games when playing against the odds. The first World Series sweep in history occurred in 1903 when the American League (AL) defeated the National League (NL) four games to zero. It was the only Series that year because the players had not yet voted to end the season after it was discovered that baseball had no post-season tournament at the time. In 1904, the AL and NL met again for the championship, this time with a best of three series used instead. The AL won both games of the series to claim its second world title. In 1907, the World Series became a best of five format and has remained so since. The AL has dominated the series since its inception with a record of 31-20. The NL has not swept an AL team since this year's series between the Chicago Cubs and Cleveland Indians. World Series sweeps have come about various ways over the years. Some teams have simply taken all the game balls and refused to give them back once the Series has ended.