Is Federer the greatest of all time?

PARIS -- It is known as the City of Light, but nothing defines this place like the glittering works of art that call it home.

There is the majesty of Gustave Eiffel's great tower, more than 1,000 feet of soaring, intricate iron; the coy Mona Lisa by Leonardo da Vinci in the Musee du Louvre; the sheer beauty of La Place Concorde. Walk across the Seine to the Left Bank, and Musee d'Orsay houses breathtaking works by Van Gogh, Monet and Manet. Not far away, "The Thinker" can be found at Musee Rodin.

You can now add Roger Federer to this lovely list.

In winning the 2009 French Open on Sunday, Federer made history. In beating Sweden's Robin Soderling, he simultaneously completed his personal Grand Slam and drew even with Pete Sampras' record of 14 Grand Slam singles titles.

How to put these achievements in context? In recent days, ESPN.com queried the experts in an attempt to assess the sprawling, intersecting legacies of Federer and Sampras.

Andre Agassi, 1999 French Open champion: "It changed my career 10 years ago and, as a result, changed my life. It was probably the most profound moment that I've ever had on a tennis court, getting over those obstacles and self-doubt that I had coming to win here.

"I think Roger, being the second-best clay-courter over the last five years, making the finals three different times, deserves this more than I did. In some ways, it almost feels like destiny for him.

"I think to win on all four surfaces, especially in one year, as Roger has had an opportunity to do a number of times in his career, is probably one of the greatest achievements in sports. To do it in a career is an achievement that I'm so proud of because every surface, every condition demands something different from you, and will reward you differently as well. From the physical challenges that exist, to the mental challenges, it's highlighted by the fact that it doesn't get done too often.

"If it weren't for some sort of freak of nature from Mallorca, he might have won this tournament probably already a handful of times. Freak of nature -- it's a compliment where I come from.

"He's an extraordinary talent, talk about grace on the court. Watching him play is something special to see. For the rest of the life, he'll know what an accomplishment that is."

Brad Gilbert, ESPN analyst: "More than anything, Roger doesn't have to answer the question about the thing missing from his résumé. His record speaks for itself.

"When he gets to 15, there's absolutely no question he's the greatest. If he stops at 14, he still has one of the greatest records. One of the greatest accomplishments of the Open era is winning on all four surfaces. That's amazing."

Mary Carillo, ESPN analyst: "Winning No. 14 at Roland Garros? Well, that's the upset. I think even Roger thought No. 14 comes in Australia and 15 comes at Wimbledon. My sense of things is he thought he would do it this year, but those were the two where he figured to win. It's just great.

"How funny is it? Federer's been the second-best clay-courter in the world for, what, four years now? Nobody had him in the pool. Nobody.

"This, to me, can tip everything for Roger. Absolutely. Does it push me closer to calling him greatest ever? Yes. It does for me. Pete made one semifinal here; Roger has five. That's a major consideration if you're going to hold them up against one another.

"In the grand scheme of things, am I willing to anoint Roger as the all-time greatest? I honestly feel like we have to wait until Nadal's career is over. I really do. I just think Nadal's going to do everything he can to win majors as well."

Todd Martin, former ATP pro: "I think it's the greater definition of his career. He has bona fide resistance now, everywhere he turns. It's not just Nadal. Sampras went through his career winning one or two Slams a year and a handful of tournaments. Federer, for a while there, was winning three Slams and 10 tournaments a year. He had no resistance. This will prove his mettle much more. It's such a departure going from clear domination; it was an utter shock to his system. Now he's won two out of the last three [Slams].

"I have a tough time believing that he won't win 15, at least. It's a bit of a rejuvenator. He can be encouraged about what the future holds as opposed to wondering and wondering and wondering. It's a relief but also a motivator."

Nick Bollettieri, coach of 10 No. 1-ranked players: "This victory gives Roger the distinction of tying Pete Sampras for the most Grand Slams in the history of our sport. Just as importantly, he accomplished this monumental task on three different surfaces; a testament to his versatility and willingness to adapt to very different styles of play.

"I believe that Roger's legacy will be years in the making. He will set the bar at a height that will be very difficult for future players to reach."

Peter Bodo, Tennis Magazine: "There's no question in my mind it's now Federer. Pete could always say, 'He's never won the French -- just like me.'

"If you're defending Pete's claim, the one thing you look at is the guy in the context of his time. To him, No. 1 was the guy who has been on top. Federer hasn't done well with Rafa.

"I think you just have to suck it up and draw the line at the Open era. But in a way, I'd like to preserve the asterisk when people have this discussion. A calendar Grand Slam is the ultimate, the greatest single achievement. There's no doubt about that."

Bud Collins, ESPN: "It's tough to talk about legacies, because [Federer and Nadal] are both young men. You just don't know how long they're going to last. I think it helps, since Pete never won this, but if the other fellow [Nadal] keeps beating him up, well …. It's a good argument [for Federer], but I personally feel Pete had tougher competition -- Lendl, Agassi, Courier. There are more good players now, but those were great players.

Matt Cronin, Inside Tennis magazine: "It's unexpected Roger got the final, but people lose in tennis, and his three main rivals all lost. All who had terrific records against him in the last year or so, all lost and he survived and won the matches he had to win. As Roger said, it would have been better if he beat Rafa in the final, but he can't control that.

"That means he's the best player of all time, with one major caveat -- his record against Nadal. All the top five guys have positive records against all their peers. Federer doesn't.

"If he turns it around somehow against Rafa in the next few years, then there's no question about it because his record on clay is so much better than Pete's."

Greg Garber is a senior writer for ESPN.com.