By the time Venus Williams won her first Wimbledon title in 2000, joining her younger sister Serena as a Grand Slam champion, there were many willing to predict a period of grasscourt dominance by the sisters.

Possessing extraordinary levels of self-belief plus the phenomenal power which would not only prove perfect for the surface but spark a revolution in the whole of the women's game, they seemed to have everything.

Not only that, but they loved SW19 - after Venus retained her title in 2001 by brushing aside the Belgian Justine Henin, she admitted victory at The Championships exceeded those experienced at other tournaments.

"I love Wimbledon," said Venus. "It's going to be a great place for me in the years to come."

Fast forward to 2008, when Venus wrapped up her fifth ladies' singles title with a straight-sets win over Serena.

"Winning it this many times definitely puts you in the stratosphere because of what the tournament means," Venus said. "Winning any tournament five times is awesome, but it has not nearly the same meaning as Wimbledon."

Last year, strange as it sounds, Venus' win was far from expected. The women's game had continued to evolve, and the sisters' habit of picking and choosing their favourite events had seen them shunted down the rankings.

Pre-tournament, the talk was not of that prospective fifth title for Venus, but rather the emergence of a pair of stars from Serbia in the shape of Ana Ivanovic and Jelena Jankovic, both of whom were heavily backed for their first triumph.

After a so-so season on clay, neither was Serena particularly expected to build on her own two All England Club titles in 2002 and 2003. Having ushered in a new era for the game, the Williams sisters no longer had top billing.

Things changed, of course. Venus, seeded a lowly fifth, eased through to the final where she beat her sister 7-5 6-4, a score that does not entirely do justice to the quality of the match they played.

This year, the pundits will not make the same mistake again.

Despite the usual storied build-up of injuries and tournament pull-outs, the Williams sisters are guaranteed to be fighting to create another piece of history.

Venus may have been humiliated by Hungarian Agnes Szavay in the third round of the French Open, losing in straight sets, including the first 6-0. Serena, pre-France, lost an unprecedented four straight matches.

But there was little else on show at Roland Garros to leave the Williams sisters quaking in fear of what was to come. Serena, despite her awful form, her dislike for clay and a painful knee injury, still reached the quarter-finals.

Williams had already shed doubt on a rankings system which placed Russian Dinara Safina at number one in the world despite having still to win a Grand Slam, as opposed to Serena's 10 career triumphs.

"We all know who the real number one is," said Serena in May. "Quite frankly, I'm the best in the world." Quite frankly, despite her Paris exit, there were few left arguing after watching Svetlana Kuznetsova win the title over stuttering Safina.

Yet since their first Grand Slam triumphs, the sisters have been continuously fighting off threats to their status as the best players in the world. It was said their dominance was over when Maria Sharapova stunned Serena in the 2004 final.

It was said again when Amelie Mauresmo matched the Williams sisters for muscle and finally kept her nerve to win her first Wimbledon title in 2006. And when big-hitting Belgians Henin and Kim Clijsters began to give as good as they got.

Now, Sharapova appears to be dicing with burn-out. Mauresmo has faded out of the elite, Henin has retired, and Clijsters has just announced her intention to begin a comeback.

All the time, the Williams sisters have reigned, all but statistically, at the top of their sport, despite spending an increasing amount of spare time pursuing other extra-curricular interests.

Venus runs a thriving fashion agency while Serena is an enthusiastic player in the US celebrity world. "I'm an actress, a model and an athlete," Serena said in 2004. "I put athlete third on the list."

If that wasn't bad enough for their opponents, Wimbledon has been proven to bring out the best of them. Serena's patchy claycourt form, even her painful knee injury, will be rendered almost irrelevant when she first steps back Centre Court.

"I love Wimbledon," adds Serena. "I love the US Open and playing on that big court, but there's something about playing at Wimbledon that I can't get enough of. Winning Wimbledon again would be great."