Billie Jean King celebrated the 45th anniversary of Title IX at the New York Historical Society.
King and friends of the Women's Sports Foundation gathered Thursday night at the museum, where an exhibit of her life and tennis career is featured at the Center for Women's History.
Title IX was signed into law on June 23, 1972. It opened doors for girls and women by banning sex discrimination in all federally funded school programs, including sports.
King says she started the Women's Sports Foundation in 1974 to "protect the sports side of Title IX, to be a guardian of it."
King won 39 Grand Slam tennis titles and lobbied for equal pay in the sport. She was joined at the event by WNBA President Lisa Borders, ESPN broadcaster Cari Champion and several pro athletes.
The New York Historical Society acquired King's archives last fall.