At a time when elements of Broadway and Vegas have invaded so much of the sports world, there is something classic about the Tour de France.

The three-week-long bike race unspools today on a path toward certain pain, physical punishment and hazards of all sorts that are unmatched in athletics.

Like completing the Appalachian Trail or running the Iditarod, riding in the Tour is at once very simple and richly metaphoric. It is heavy on steak, light on sizzle. It is exquisite self-flagellation, whose redemption comes in a commingling of anguish and glory.

The Tour is decidedly medieval. With its platoons of the strongest and steeliest cyclists, astride the finest two-wheeled steeds that modern engineering can devise, traversing mountains and misery in equal measure and adhering to a code of honor that governs everything from bathroom breaks to what to do if your key rival crashes (wait politely for him to get back on the bike, of course), the Tour resembles nothing so much as a heroic quest from the days of King Arthur.

Sure, most of the competitors are anorexic-looking, hollow-cheeked fellows with wan white chests and baby-smooth legs, wearing flashy Spandex and oversize insectoid sunglasses. To many, they may look more like large crop pests than warrior princes.

But stick with this for a while. Throw five-time winner Lance Armstrong -- the fatherless Texas boy who vanquished cancer on his way to becoming a pop icon and possibly one of the greatest athletes of all time -- into the mix and you have so many parallels to mythic hero tales that fans need look no further for their 21st-century action figure.

Perhaps this is why the Tour has fascinated Europe for the past century, and its fame is growing steadily here. It is the most storied contest in a sport that runs on technology (one of Armstrong's bikes incorporates materials used in space satellites). Yet it follows an ancient formula, where men are called to venture into open country and prove themselves against their rivals and against their own weaknesses. Tackling the slopes of the Pyrenees (during the race's second week) and the Alps (in the third), riders will crack, get dropped, slip backward, fall over sideways. Others will claw and grind their way up to the finish, only to face the same pain, fear and difficulty the next day, and the next.

"It's a mirror-like reflection of real life," says Bob Roll, a former pro bike racer and a Tour commentator for cable's Outdoor Life Network. "It's like a soap opera unfolding. . . . It's a melodrama that guys are actually going through. Once you identify the strengths and weaknesses, you go through it with them."

No rider makes his way to the finish at Paris's Arc de Triomphe alone.

Teamwork is essential to the race: Eight pack dogs surrounding the alpha male. Bike racing is about working through pain, and beating back the wind. Riding six- to eight-hour days on the open road, you need your buddies around you as human windshields.

If the team leader is a knight, his teammates (known by the French term "domestiques") are his squires. There's a feudal sense of hierarchy on the teams, designed to keep the leader in the best winning position throughout the race. This is especially true on Armstrong's U.S. Postal Service team, which adheres to an all-for-one strategy. If deep within your domestique heart lies a grain of ambition to steal a Tour win away from Armstrong, you belong somewhere else. (Two of his chief rivals this year -- the American Tyler Hamilton and Spain's Roberto Heras -- are former teammates who defected to lead teams of their own.)

On the Armstrong Express, your job is to suffer deeply each day to protect one guy.

The teammate in front is battling wind resistance; everyone behind benefits from a 25 to 30 percent reduction in effort by riding in his slipstream. As lactic acid builds up in the muscles of the man heading into the wind, his thighs begin to burn. When he can no longer keep up the necessary pace, he fades back, and the teammate next in line takes his place.

For much of the race, Armstrong rides relatively coolly a few men behind. Only at decisive moments in the mountains does he "attack," accelerating at a pace that tears the legs off his competitors. If he's thirsty, hungry or needs a rain jacket, designated teammates drop back to the team car to load their pockets with supplies.

Domestiques are part mule, part Marine, fueled by loyalty to their leader.

"A lot of being a domestique goes against what America sees as the elite athlete," said Ted Butryn, a professor of sports sociology and psychology at San Jose State University. In this country, the typical professional sports star is admirably self-indulgent -- holding out for a contract, negotiating a deal, celebrating in the end zone. Compare this with the domestique, who gets respect in the subculture of cycling but is completely anonymous beyond that. "Where we're socialized to succeed, to work hard, what if your success is predicated on somebody else succeeding?" Butryn asks.

Postal team member George Hincapie said recently: "I'm not really there for the recognition." He was in the Pyrenees and he had just finished a six-hour training ride so punishing that his speech was slurred. "I love the sport and I appreciate that I get to do it for a living."

Hincapie, who is the only teammate to have squired Armstrong through all five Tour wins, marks his achievement in small, personal ways.

There was the day last year when Armstrong's handlebars caught on the straps of a feed bag dangling from a fan's hands and he slammed to the asphalt.

Doubts about Armstrong's fitness had been gathering throughout the race, but he went on to win that stage, thanks to Hincapie, whose push into the wind had brought his leader to the base of the Luz Ardiden peak in such good fashion that he could go on to conquer it. Hincapie slogged across the finish some 20 minutes behind. Armstrong, shaken but victorious, was already on the podium, acknowledging the comrade who had helped put him there.

"I was going through the crowd," Hincapie said, "and I pointed to him, yelling at him -- and he was pointing to me. It was funny; we both knew he had just jumped from not being sure of himself to being sure of himself -- and being the same old Lance."

Brotherhood -- and fealty -- alive on a Pyrenean crest.

Tour de France history is full of examples of heroic exertion and gallantry. To be sure, there are also rats and opportunists and selfish "wheel-suckers," those who take up real estate in the slipstream and never pull at the front. As in many endurance sports, doping allegations and suspicions have dogged some of the favorites. (Armstrong included -- an accusatory book has just been published in France by two journalists, British and French, though they acknowledge they have no proof of drug use and Armstrong, who is tested incessantly, denies the rumors.) Just in the past week, four riders have been forced to pull out of the Tour because of suspected drug use.

But no other sport boasts a champion like five-time Tour winner Eddie Merckx, the Belgian considered to be the greatest cyclist of all time for his unmatched stream of victories in races besides the Tour.

Merckx's 1975 attempt at a sixth Tour win was plagued with disasters. During one stage a spectator socked him, injuring his kidneys. Doctors advised Merckx to stop. He refused. Two days later, he touched wheels with another rider and crashed. Nose smashed and jaw broken -- and wired shut -- he sucked food through a straw for the remaining days of the race. Yet he wouldn't quit, even though at his daily news conferences, the whole dais would be shaking because Merckx, racked with pain, was shaking.

"Journalists followed him everywhere, waiting for him to retire," recalls veteran cycling commentator Phil Liggett. "And he said, 'You can forget it. I'm not giving up, even if I can't win the Tour de France. You will say that the guy who wins only did so because I abandoned.' "

Merckx soldiered on, heaving himself into second place behind Frenchman Bernard Thevenet.

In the process, said Liggett, the vanquished winner "made Thevenet look fantastic."

In its best moments, the Tour highlights honor as much as it does brute strength. A worthy contender pauses for the opponent who crashes, so as not to gain advantage purely because of luck, an icy patch, melting tar, etc. This happened a few years ago when German rider Jan Ullrich, Armstrong's greatest rival, ran off the road and flipped over his handlebars. Armstrong, already wearing the leader's yellow jersey, waited for him to catch up. Last year, Ullrich returned the favor after Armstrong was downed by the errant feed bag.

And if the Yellow Jersey needs to pull over to answer nature's call? You do not choose this moment to attack. It simply isn't done -- you risk being pelted with water bottles and dragged back to the peloton (as the mass of riders is called) for verbal flogging in half a dozen languages. One needs friends in the peloton. Best not to tick them off by flouting decorum.

Besides, it's just not sporting.

Lance Armstrong, as anyone glancing at a magazine rack lately knows, is hoping to achieve what no man ever has: a sixth Tour victory. That sixth heavy chalice -- the trophy given to winners, along with about $400,000 -- is the Holy Grail of cycling.

Who better than Armstrong to attain it?

"He's a Grail knight," said University of Maryland English professor Verlyn Flieger, who specializes in myth. Like Galahad, the Round Table knight who finally succeeded in his quest for the Holy Grail, Armstrong grew up without his natural father, who left his mother when he was a baby. Like many an ancient hero, Armstrong's will to succeed has been forged in fire: testicular cancer, which invaded his lungs and brain and nearly killed him in 1996, when his pro cycling career was starting to flower.

Starting today, the 32-year-old Armstrong is engaging in the ur-contest: against himself. "That is the more interesting and psychologically difficult battle," said Flieger. "He's battling against his own record. And he's battling against his own body as he approaches the point where his strength is not up to the task."

What if he loses? Judging by precedent, Armstrong can still win in the public eye. Loss humanizes a hero. We like flawed heroes, as long as they're more hero than flaw. (Mike Tyson, for example, has the proportions all wrong. Babe Ruth got them right.) Losing, in fact, would put Armstrong in company with the legendary knight with whom he shares most of a name: Lancelot. It was gifted, charismatic Lancelot who first got close to the Grail. Faulted by God for his moral shortcomings -- messing around with the king's wife -- Lancelot was granted only a vision of the Grail, and not the prize itself.

Yet Lancelot's story is an enduring favorite. Torn between his passion for God and for Guinevere and his desire to excel, Lancelot became a knight for the ages. "We like him because of the failing," Flieger said, "because the failing is married to his heroic effort and to the conflict within him."

Divorced in December, Armstrong has been inseparable from rocker Sheryl Crow for much of the past year. Has she been too distracting? The love affair will undoubtedly be factored into any failure. Armstrong may have more in common with Lancelot than he'd like.

Yet as his perseverance in the Tour de France has shown us, he is perfectly suited to attempting what no one else has ever done.

This is exactly what we look to heroes to do.

Knight and squire: Lance Armstrong follows teammate Viatcheslav Ekimov in the 2003 Tour de France. This year's quest starts today.Brotherhood of sweat and pain: Lance Armstrong, left, and George Hincapie of the U.S. Postal Service team, and Manuel Beltran, right, of Spain, train in Belgium Thursday for the Tour de France. In the race they'll face danger and exhaustion.