Tennis legend Billie Jean King (1943– ) was born on this day in Long Beach, California. A role model for today’s players, she became the first woman athlete to earn $100,000 in prize money in a single year (1971).

“Tennis is a perfect combination of violent action taking place in an atmosphere of total tranquility,” she observed. King became known for her fierce competitive spirit, power-hitting, and fearless net-charging play.

Because tennis is a sport where women can compete with the same visibility as men, where a woman could “be a champion and a lady at the same time,” King became a catalyst for equality and change.

“That’s the trouble with this sport,” she said in an interview. “We’ve got to get it off the society page and onto the sports page.”

In 1973, she defeated male tennis pro Bobby Riggs, the self-proclaimed “male chauvinist,” to win $100,000, the largest purse ever paid for a single tennis match. The hyped “Battle of the Sexes” filled the Houston Astrodome with more than 30,000 fans and was watched by some 60 million viewers on worldwide TV.

As Frank Deford of Sports Illustrated wrote, King didn’t just raise consciousness—she changed it.

King captured a record 20 Wimbledon titles, helped establish the first major women’s sports magazine, and founded the Women’s Tennis Association. Still a strong advocate for women’s rights, she has continually pushed for equal prize money in tennis and beyond.

“Treating women as less valuable than men generates ill will that is disproportionate to the amount of money you are saving,” she argued. In 1987, Billie Jean King was voted into the International Tennis Hall of Fame.