Stefanie Maria Graf (, German: [ˈʃtɛfi ˈɡʁaːf] ; born 14 June 1969), known professionally as Steffi Graf and preferring to be called Stefanie since 2001, is a German former professional tennis player. She was ranked as the world No. 1 in women's singles by the Women's Tennis Association (WTA) for a record 377 weeks, and finished as the year-end No. 1 a record eight times. Graf won 107 singles titles on the WTA Tour, including 22 major women's singles titles, the second-most since the start of the Open Era in 1968 and the third-most of all time. She is the only tennis player to have won each major singles tournament at least four times—a quadruple career Grand Slam. A teenage phenomenon, Graf became the youngest player to appear in the main draw of a major at the 1983 French Open aged 13. She improved over the following years and emerged as the player who ended Chris Evert and Martina Navratilova's dominance on women's tennis, winning her first major at the 1987 French Open. In 1988, Graf ascended to dominance, becoming the first tennis player to achieve the Golden Slam by winning all four major titles and the Olympic gold medal in the same calendar year. The following years saw her remain the best player in the world, but struggle with injuries and the rise of young rivals, especially Monica Seles. After the stabbing of Seles in 1993, Graf returned to dominance on the women's tour for several years. After more injuries in 1997 and 1998, in 1999 Graf captured her 22nd and final major title at the French Open, reached the Wimbledon final, and retired from the sport, aged 30 and ranked as the world No. 3. Graf's game was noted for versatility across all playing surfaces, footwork, and powerful forehand drive. Her athletic ability and aggressive game played from the baseline have been credited with developing the style of play that dominates today's game. Billie Jean King said, "Steffi [Graf] is definitely the greatest women's tennis player of all time." Graf was named the greatest woman tennis player of the 20th century by the Associated Press; asked in 2016 to name the greatest players of all time, Serena Williams answered Graf and Roger Federer. Graf was inducted into the Tennis Hall of Fame in 2004. Along with Boris Becker, Graf is considered instrumental in popularizing tennis in Germany. She has been married to fellow tennis player Andre Agassi since 2001. They have two children.