The fame of Achilles has lasted for more than three millennia, his name enduring through the inexorable march of centuries and civilizations as the prototype for the ultimate warrior, a godlike paragon of valor and manly beauty. The incomparable fighter whose rage nearly doomed his fellow Greeks during the Trojan War, Achilles was immortalized in the Iliad as the pivotal character who finally accepted his fatal destiny and helped to defeat Troy.

Heroism? Beauty? The guy who saves the day, seduces the girl, turns the tide of history, and has audiences swooning all over the world? In the kind of enormous Hollywood epic that can transform a mere movie star into an icon for the ages?

Precisely the type of part Brad Pitt has spent the last dozen years rejecting.

So when Troy opens on May 14, the $170 million saga will mark a major milestone in his stubbornly iconoclastic career: Brad Pitt has stopped running from his inner superhero and turned around to embrace his own destiny.

“I finally caved,” he says, those famous eyes twinkling.

Pitt’s aesthetic – austere and somewhat unforgiving, all hard edges and unyielding materials – could soon prove problematic, however. Aniston has been making nervous comments about the difficulties of babyproofing the rough-hewn stone floors, the glass dining table, the gleaming metal and leather furniture. But Pitt just shrugs and grins.

“I have a different theory: you gotta fall down; you gotta learn,” he says. Besides, the drawbacks of what was supposed to be their dream house offer an excuse to move again. “I see this as a good place to get started, but I’m gonna build from the ground up – I have to,” he says. Restless as ever, he’s already looking ahead to the next challenge.

Which is, in a nutshell, the simplest explanation for why the heartthrob who’s perennially at the top of the world’s sexiest-man-alive lists has defied myriad pressures to play the hero in any number of movies.

“It’s very hard to hit blockbuster status without playing to the lowest common denominator, and Brad has never chosen to do that,” observes Doug Liman, who directed Pitt and Angelina Jolie in the upcoming Mr. and Mrs. Smith.

“I wanted to go explore some of the other stuff before I got cornered,” Pitt explains. “My favorite actors and performances have more of a character slant. I always felt like I could go back and do the leading-man thing. It was something I could fall back on, but I didn’t see that as a way to longevity. I saw it as a way to get in the door, but I don’t think it’s going to keep you there. You see the consumptibility of the flavor of the month…”

He pauses. “Is ‘consumptibility’ a word?” He pulls out a dictionary and looks it up; when confronted with a gap in his education, Pitt is always interested in filling it. We discuss variations of the word “consume,” and then he continues, “There are films that we just consume, and there’s a place for pure entertainment, but that’s not what interests me about movies. I moved out here because of the films that showed me another culture, another way of life–that made me understand something I didn’t understand, that spoke of something in a way I could never speak it. For me it’s just about following what’s interesting at the time.”

He’s proud of his choices. “How about Kalifornia – I dare you to put a better white-trash sociopath on the screen,” he says in a rare moment of boastfulness.

“He’s gotten away with it because you can’t take your eyes off him,” says Akiva Goldsman, the producer of Mr. and Mrs. Smith.

“Brad Pitt is one of those people who transcends box-office success and the failures of his movies; he’s box-office impervious,” says Doug Liman. “We all love him – all of America. We don’t all want to go see some of the movies he chooses to make, because he makes bold choices, but he’s trying to push himself.”

Even when Pitt has signed on for what looked like a big-box-office movie, he’s risked playing opposite leading men whose star power could overshadow his own: George Clooney in Ocean’s Eleven, Robert Redford in Spy Game, Harrison Ford in The Devil’s Own, Tom Cruise in Interview with the Vampire.

Big money hasn’t been a priority, either. “I don’t really care. I’m not the best of businessmen, I guess,” Pitt says. “It’s never been my first concern. To this day, I have yet to receive a full $20 million, although I have been offered more than that. I took half of that to do Troy, with profits on the other end. I like being the flighty artist guy unencumbered by those things. At the same time, I’ve done Japanese commercials, so let’s be honest.” (Pitt has earned millions modeling Edwin Jeans and Tag Heuer watches in Japan.) “My choices have not been all about art for art’s sake; I’ve certainly succumbed to some of the pressures of what others may want. It’s a constant negotiation. But maybe I did run from it for a while. I think that’s a fair assessment.”

Playing Achilles, Pitt even had to be coerced into what others instantly pegged as the role of a lifetime for him. “I almost didn’t do it,” he admits. “It just seemed too obvious.”

On closer inspection, however, Achilles offered a rare opportunity. “It’s not at all a straightforward leading-man role. He’s much more complex, controversial, and interesting,” says Wolfgang Petersen, who directed Troy. “Yes, he looks beautiful; he looks like a god, but he’s a haunted person, driven, pained–a very modern kind of man. He has a very dark soul. There are a lot of demons inside him, and that suits Brad. Brad really nails it.”

Arrogant, proud, and full of fury, Achilles is almost superhuman in his courage and leadership on the battlefield, but all too mortal in his flaws.

And Pitt, who can glower and smolder with the best of them, found that Achilles “really struck a chord with me,” he says. “He’s extremely violent, but there’s a juxtaposition of violence and tenderness. He wasn’t formed by any belief system; it was strictly trial and error, and yet he was able to take those experiences and create himself from it. He’s conflicted about going to war; he wrestles with that decision. He’s a hero, but that’s not enough. There’s this hunger for something more, this need to transcend everyday life–the need to grab more, to discover a mythic life and transcend the limits of mortality. But he’s not such a nice guy. He desecrates the body of Hector in a horrible, vengeful way.”

To get in character, he threw himself into the role with a grim intensity. “I lived a complete and utter monastic life; I had to,” says Pitt, who spent five months filming in Malta and Mexico. “This guy had so many walls up; I had to live inside those walls. There were times when Jen would look at me like I’m out of my mind. Malta is just a big rock island, and I lived up in this 300-year-old stone house on a mountain. I didn’t run the air conditioner or anything; I wanted to feel those 100-degree nights. People always bring up what Laurence Olivier said to Dustin Hoffman – ‘Dear boy … why don’t you try acting? It’s so much easier.’ But it doesn’t work that way for me. We do give up our lives for a while, doing a movie like this. It’s not necessarily fun. But I’m not a big proponent of happiness. I think it’s highly overrated.”

He shoots me a sly smile. “I think misery is underrated. There’s so much value in that. You can’t have one without the other.”

The smile vanishes. “I just want to be engaged,” he says.

Although the plot twists of the Iliad often hinge on revenge, it’s a theme Pitt has long tried to avoid in his work. “I really despise a vengeance film,” he says with uncharacteristic vehemence. “It’s too easy; it’s too simple. I really stay away from those films.”

He justifies his participation in Troy by reading an anti-war message into the Iliad. “Achilles goes for vengeance, and it shows the emptiness of vengeance,” Pitt maintains. “It’s about one civilization trying to overthrow another civilization. What he’s trying to say is, we can’t be drawing these boundaries – us versus them. We’ve got to accept our common humanity. The hatred of men is born; it dies. The things that separate us – they die. The thing that’s everlasting is our humanity.”

After Achilles kills the Trojan prince Hector, his father, King Priam, played by Peter O’Toole, begs for the return of his son’s body. “As walled up as Achilles is to any kind of emotion, Priam comes in and disarms this hardened warrior with the weapons of peace, which are words,” Pitt says. “There’s a line that brought me to my knees, that still gives me gooseflesh. Achilles says to Priam, ‘If I do this for you, you’re still my enemy in the morning.’ Priam’s response is ‘You’re still my enemy now, but even enemies can show respect.”

Pitt sighs. “That scene was one of the high points of my mini-career.”

Even the august O’Toole approves of his younger co-star. “He came through,” says O’Toole. “He was completely prepared for every scene we did. Not once did he ever lose one thread of authority. He’s maturing. He’s always had a frankness, a disarming sensitivity and vulnerability, and that’s becoming stronger. He’s a good actor, and he’s going to be a fine actor.”

“This guy’s supposed to be the greatest warrior of all time; I had to get my ass in shape,” Pitt says. “I changed my life completely. I quit smoking – and let me tell you, I was a professional smoker, and I still miss it. I know she was trying to kill me, but I really loved the b*ch. But I wanted to see how far I could go with my body; by the time the movie was over, I’d been on this diet and workout plan for over a year. I wanted physical dominance; I wanted to have that ability and endurance in my arsenal. I wanted to have the strength to do this and not be dogging after a take or two. There was a tremendous amount of fighting with swords and spears, and everyone was at the top of their game.”

Tall and limber, Pitt still looks boyish in his blue jeans and buzz cut. But he turned 40 last December, and a cynic might wonder whether he finally stopped avoiding heroic roles because the expiration date for their availability appeared on the horizon, distant though that may be.

“It’s not that I was trying to avoid anything,” he protests. “I only have something to offer if I’m interested in it. I am dead to repetition. That’s just not what I do, not what I’m made of. So when I have repeated, it’s been rather flat. I don’t get the jones; I don’t get the discovery.”

When I ask who his own heroes have been, he invokes the names of architectural icons. “I don’t know that I have any heroes,” he says. “But I’ve certainly got a few men I respect very much, and one would be Frank Gehry. He said to me, ‘If you know where it’s going, it’s not worth doing.’ That’s become like a mantra for me. That’s the life of the artist. The life of the artist is not about making sure it’s successful.”

In many ways, the words he chooses to describe Achilles reflect his own journey: rejecting the belief systems that surrounded him, making his way through trial and error, creating a new self out of the experiences he encountered, always eager to grab more. While he is tactfully elliptical in discussing his upbringing, it’s clear he found it too confining.

“I grew up in the dogma that told you what you can do and what you can’t do,” he says. “I see that as very dangerous to the growth of an individual. I am such a believer in live and let live. Don’t tell me how to live; let me live my life, and I’ll let you live your life and respect our differences. All our puritanical values drive me crazy. We end up policing the world, trying to impose our values on other people. All that seems absolutely ludicrous to me. I don’t want to attack anyone’s faith, but at a certain point I find it stifling. My main problem with religions is that they’re separatist. They draw lines: ‘Ours is the best!’ There’s a harmful conceit that lies at the heart of all these religions: ‘My team’s better than your team!” It’s a high-school mentality. I couldn’t relate to it even in high school.”

But he has a renewed respect for Greek mythology. “It seemed to really value the ups and downs in the wheel of fortune,” he observes. “There seemed to be a much greater understanding of human nature, instead of this crazy concept that we all have to be good all the time.”

Fortune has been extremely kind to Brad Pitt, something he has understood since he was very young, when he recognized that his extraordinary looks conferred extraordinary advantages. “I remember being in early elementary school and realizing that things are not fair,” he says. “I was well aware that I could get away with more. It kept me up at night. I talked to my mom about it. She told me that just meant I had a greater responsibility. I had tremendous guilt over the lack of fairness, although at times I could be a little [naughty] with it. Maybe it was those very times that would bring me to guilt.”

“He’s a scoundrel,” says O’Toole with a wicked laugh. “He led me, his elderly colleague, astray more than once.”

And what was the nature of their transgressions? “I can’t remember,” claims O’Toole.

While Pitt has deliberately discarded some of his midwestern roots, others are deeply embedded in his personality. Despite superstardom, he is resolutely unpretentious. “He’s one of the most down-to-earth people; he’s a very real man,” says Angelina Jolie, Pitt’s co-star in Mr. and Mrs. Smith.

Pitt’s movies tend to perform better abroad than they do in America, and the rabid attention generated by international fame is a constant challenge. “One night in Malta everyone went out, and word got out that Brad was there, and it was like ‘Elvis is on the loose!'” reports Eric Bana. “You wouldn’t want to be him and Jen for all the tea in China. But he’s very, very cool about it. He’s very aware of what people’s expectations are, and he knows how to handle it.”

According to Pitt’s fellow cast members, he doesn’t even pull rank. “He’s really generous to work with. I very much felt an equal,” says Rose Byrne, who plays the vestal virgin who succumbs to Achilles’ charms in Troy.

“He’s a humble guy,” says Wolfgang Petersen. “He gives everybody the feeling that he’s honored to work with them, and that creates a wonderful atmosphere.”

Treating other people that way was drilled into Pitt early on. “Humility is a big part of where I grew up,” Pitt says. “But I’m a dinosaur. Rap culture is all about inflating yourself… ‘I’m the one! You’re a piece of sh*!’ That kind of pride, inflating yourself – it was considered vulgar where I come from.”

When he hit Hollywood, his laconic, awshucks-I’m-just-a-good-ol’-country-boy persona may, at first, have been misleading. “In my time out here, I’ve been underestimated a lot,” he observes. “Maybe it was because of the DNA. Maybe it was because I smoked too much of that stuff that just turned me into a doughnut. At some point, I realized it gave me the opportunity to surprise, so I grew to embrace the underestimation – to just sit back and say, ‘You’re setting yourself up!'” He flashes that rakish I’ve-got-a-secret grin he used so effectively in Thelma & Louise, just before he stole their money and sealed their doom.

Then fame exploded in his life like a bomb. “It was really overwhelming to me when it went off,” he says. “There was this discombobulating cacophony; I couldn’t find my bearings in it for a while. At 30, I was so pliable, blown around by the bombardment of everything coming at me. I operated mostly on instinct. Now I’m more bulletproof.”

But during those earlier years Pitt sometimes struggled with what he has referred to as a “congenital sadness.” Since then it seems to have receded into the background. “I know what to do with it now,” he says. “I keep it in check. It would always be present, but it could be just a little nick over in the corner.” He spreads his arms wide, as if his life were a big painting and the darkness a mere shadow at one edge. “I think other things are more present, and they overwhelm it now.”

His life with Aniston has clearly provided a solid center. “Her emphasis is the home, friends, and family,” Pitt says. “We all kind of crowd around her like moths to the flame. She’s like a magnet. She brings a lot of people together that way. Jen’s the fireplace; she provides the warmth.”

But they both bridle at their media image as America’s sweethearts. “Neither of us wants to be the spokesman for happy marriage, for coupledom,” says Pitt. “I’ll tell you what I despise: this two-becomes-one thing where you lose your individuality. We don’t cage each other with this pressure of happily ever after. You figure it out as you go along. We feel it out, rather than setting policies and rules. Jen and I always made a pact, that we’ll see where this thing is going. I’m not sure it really is in our nature to be with someone for the rest of our lives, just because you made this pact. You keep going as long as you keep growing. When that dies, we do. But it constantly surprises me. Just when you think you’ve gotten all you can out of it, you get knocked upside the head. It’s good fun. We still have that friendship; we still have a good laugh, which can go in and out depending on the dynamics and outside influences. It’s complicated, but that’s what keeps it interesting. We’re good at getting sh* on the table. Then she tells other people and I get mad.” He lets loose with a big belly laugh.

Their fans are now obsessing about when Brad and Jen will start a family, generating media attention so intense that Aniston spoofed it in a paparazzi send-up on Saturday Night Live last January. “It will happen when it happens,” says Pitt, who is eager to have children. “I’ve got friends with kids, and I’ve got nieces and nephews, and they just bring out a joy I’ve gotten from few things. I am selfish, so I worry about having to give up my time, but I gotta go see what it’s about. I think I’ve got a lot of stuff to tell them, and the idea of being responsible and setting someone loose in the world sounds really fulfilling.”

So how many kids does he want? “I’ll go till someone says stop. I would love all girls. Guys – I know they’re going to be pissed off at me. I know I’ll f** ’em up somehow.”

Even the thought of aging fails to shake Pitt’s equanimity. “Sooner or later we have to face that thing of not being viable in the fame game,” he says. “It all goes away. That’s the first little death, facing up to not being in the ring anymore, having to watch from the sidelines. It seems to me that you can still find those pleasures without still being in the fame game; that’s an ego issue.”

Indeed, he claims to have enjoyed turning 40. “I felt privileged,” he says. “It means no more excuses, which I like. I just feel like I’m improved. I like the general label of new and improved, or old and improved, as the case may be. I’ll trade that for the deterioration of the body, or whatever else it brings. I know it’s impending.”

He grins. “I know there’s a midlife crisis on its way. I’m sure there’s some more rude awakenings yet to come. But I like it like that. I like the unknown. It’s just more vibrant that way. It’s f**ing interesting, isn’t it?”

Things certainly seem to be going well at the moment. After completing Troy, Pitt filmed Mr. and Mrs. Smith, a dark comedy about husband-and-wife assassins who are assigned to kill each other. “It’s not meant to be taken literally; it’s one big metaphor for marriage,” Pitt explains. “Doug Liman’s guiding sentence has been ‘Superhero sh* is easy; it’s marriage that’s hard.'”

Pitt then went directly into Ocean’s Twelve with George Clooney, Julia Roberts, and Catherine Zeta-Jones “I’ve never worked so hard in my life,” he says. Making so many movies back-to-back is not his usual style; before beginning Troy, he had spent two years not working, partly by design and partly because of projects that fell through. “I do time off really well,” he says. “I’m too good at it. But after the two-year period, I’m itchy.”

The hiatus has rekindled his enthusiasm for acting. “I love it now. I’m really excited,” he says. “I’ve got a new take on what I’m doing here, so I want to go out and work. I know what I’m after, what I have to offer. I’m more aware of what I can bring to a part, rather than another actor. I guess what I understand now is that there’s room for all of us. You want to earn it, but that’s a dangerous game, because then you’re still trying to answer to somebody else. You have to earn it for yourself. That’s why it’s great to be 40. I know what my strong points are, but it took all this foraging in other territories to figure this out.”

The previous week, while we were talking about his 40th birthday and how he feels these days, he’d said, “I’m happier than I’ve ever been.” But his tone was mocking, as if making fun of the inevitable tabloid headline. “Don’t write that,” he added, pointing a finger at my notebook.

Now I’m preparing to leave, and Brad walks me to the front courtyard, where my car is parked. Jen comes downstairs to say good-bye as well. Behind them, the beautiful house glows in the twilight.

“I’m happier than I’ve ever been,” Pitt repeats. His tone is still light and sardonic, but this time he doesn’t tell me not to write it down.