At the 40th anniversary of the Family Circle Cup tennis tournament in Charleston, members of the "Original Nine" who started the Women's Tennis Association in the year 1970 were honoured.

Valerie Ziegenfuss, Billie Jean King, Nancy Richey, Jane "Peaches" Bartkowicz, Kristy Pigeon, Judy Tegart Dalton, Kerry Melville Reid, Rosemary "Rosie" Casals and Gladys Heldman, mother of Julie Heldman are the "Original Nine" founders of the women's professional circuit.

It was these nine female professional tennis players who rebelled against the United States Lawn Tennis Association (USLTA) and later set up the Virginia Slims Circuit which went on to become the WTA Tour. They revolted against the extreme inequality in the amount of prize money paid to male tennis players and to female tennis players.

Prior to the establishment of the association, male and female tennis players were treated quite differently in terms of the prize money they received.

As per reports, at the first open tournament, the 1968 British Hardcourt Championships held in Bournemouth, men's singles champion Ken Rosewall earned $2,400 while the female winner received only $720.

The situation was very similar during the second Grand Slam tournament of the open era, when male winners received more money than their female counterparts. The situation became worse in 1970 when tournaments offered four times more prize money to men than they did to women.

To end this inequality, the nine tennis players started a campaign aiming to reduce the inequality between the prize money purses for men and women.

Although the team met with many failures during their initial attempts, they were eventually allowed to set up their own tour of eight professional tournaments in 1970. This independent women's professional tennis circuit provided more equal prize money than had been provided previously by the USLTA and other organizations.

Despite the USLTA's suspension of the "Original 9" from its tournaments, by the end of the year the Virginia Slims Circuit reportedly was able to boost its numbers from nine to forty members, which helped pave the way for the first annual Virginia Slims Circuit in 1971.

Start the slideshow to catch a glimpse of some rare undated pictures of the "Original Nine" along with their recent images at the 40<sup>th Family Circle Cup tennis tournament: