Family Tragedy and Life-Threatening Illness As Serena and Venus Williams Have Fought Their Toughest Battles Off the Court

To truly dominate a sport, as Serena Williams and Venus Williams have with women's tennis for the better part of 20 years, there's an almost incomprehensible amount of dedication and work—physical and mental—that goes into being the very best.

The Williams sisters have tirelessly put in that work, even when the injuries piled up and the call of Hollywood, fashion and lucrative non-tennis pursuits beckoned. Subsequently, they have dozens of singles and doubles titles and millions of dollars to their name.

But Venus and Serena weren't just faced with petty distractions over the years. Along with the normal pressures that come with being expected to win, all the time, they've played while carrying the weight of their place in history with them at all times as two of the most prominent black female athletes ever in a predominantly white sport—who also helped popularize women's tennis the world over and became the most famous American tennis players of any sex competing today.

So there's that. And in the meantime, they've played through and battled back from some seriously difficult setbacks, any one of which could've steered a less driven athlete into retirement.

Venus made her professional debut at 14, in 1994—and Serena followed a year later, also at the age of 14.

They were famous upon arrival thanks to their fascinating back story—they spent their formative years in Compton, Calif., and were groomed for greatness by father and coach Richard Williams, who decided when his daughters were barely walking that they would be tennis players—and the fact that they were still giggling teenagers with on-trend beaded hairdos.

Richard, a one-man PR machine for his daughters who boldly stated right out of the gate that Serena was the better player of the two, became a fixture on the tennis circuit, as did the girls' mother, Oracene Price. The parents divorced in 2002 after having already been separated for years, but each still showed up frequently to support their daughters. If one wasn't there, then the other almost surely was.

The Williams sisters have never not been a draw, and their head-to-head meetings were always hot tickets. However, John McEnroe(fancy that) made headlines when he commented while in the TV booth during their 2000 Wimbledon semifinal, "Serena may not be allowed to win. Richard may have something to say about this." He could not have been that serious, but the idea took hold and briefly spiraled out of control.

In 2002 the Williams sisters skipped the Masters tournament at Indian Wells, perhaps the biggest non-Grand-Slam event on the tour, after feeling that they had experienced racially motivated animosity from the crowd in 2001. Another player had made a crack before Venus and Serena were set to face off in a semifinal that Richard would decide ahead of time who won. Venus pulled out of the match citing an injury right before game time, prompting major boos, and then Serena was booed heavily during the final, which she won.

The rumor about their father fixing matches, deciding which sister would win and when, had picked up steam.

"Everyone has their own opinion. It's not a true opinion at all. Everyone makes their own comments. That's how rumors get started and I guess rumors are more exciting that the truth," Venus said after she withdrew from the semifinal.

Two weeks later, Richard Williams said he had overheard racist comments in the stands when he and Venus showed up to watch the final. Breaking her silence on her experience, Venus told reporters, "This country has a history of treating minorities badly, and that's sad because it is a country of promise."

The sisters boycotted the event for 13 years, finally returning in 2015. "The under­current of racism was painful, confusing and unfair," Serena recalled her experience in an essay for Time after announcing her intent to play there again. "In a game I loved with all my heart, at one of my most cherished tournaments, I suddenly felt unwelcome, alone and afraid...Emotionally it seemed easier to stay away. There are some who say I should never go back. There are others who say I should've returned years ago. I understand both perspectives very well and wrestled with them for a long time. I'm just following my heart on this one."