The Open Era in tennis began in 1968. Prior to this, only amateur players were allowed to play in many of the top tournaments, including the Grand Slam events. The exclusion of professionals meant that tournaments often did not feature the best players of the era. Rod Laver in 1969 , Margaret Court in 1970 and Steffi Graf in 1988 are the only players in the Open Era to win all four of the Grand Slam tournaments in a single year.