HBO has confirmed the unexpected death of actor and producer James Gandolfini, who passed away at age 51 while traveling in Italy. At press time, the cause of his death was unclear, with several outlets reporting a heart attack or a "sudden stroke." He was due to appear at the Taormina Film Festival in Sicily, where he was slated to paricipate in a panel discussion with director Gabriele Muccino.

While Gandolfini appeared in countless film and television roles, ranging from comedies (like Armando Iannucci's wickedly skewering Washington satire In the Loop) to hard-hitting dramas like Kathryn Bigelow's Zero Dark Thirty, it was his visceral turn as deeply troubled mobster Tony Soprano, the pater familias of a New Jersey crime family and a domestic one, on HBO's The Sopranos, which won him accolades from critics and viewers alike. During the drama's acclaimed six-season run, Gandolfini would win three Emmy awards for Best Actor for The Sopranos (he was nominated six times), widely regarded as one of the best television shows ever to air—it was recently named the best written show in history by the Writers Guild of America—and one that ushered in a new Golden Age for television.

"We're all in shock and feeling immeasurable sadness at the loss of a beloved member of our family," said HBO in a prepared statement. "He was a special man, a great talent, but more importantly a gentle and loving person who treated everyone no matter their title or position with equal respect. He touched so many of us over the years with his humor, his warmth, and his humility. Our hearts go out to his wife and children during this terrible time. He will be deeply missed by all of us."

With his death, Hollywood has lost one of its finest veteran actors. With The Sopranos, Gandolfini delivered a searing and deeply complex performance that captured the rage, sorrow, and frustation of the modern American male. As played by Gandolfini, Tony Soprano was full of contradictions, a complex man whose struggles with depression and panic attacks humanized him despite the violence he perpetrated on those around him. (It was hard not to love him when even his desperate, harried mother wanted him dead.) Prone to violence, Tony Soprano represented the unfettered darker impulses of the id, while also remaining intriguingly relatable. Even as the character plotted for control of a New Jersey criminal enterprise, he struggled to keep his own family together.

Gandolfini's Tony Soprano, though an anti-hero through and through, subverted the audience's expectations about what a television protagonist should look like, with Gandolfini the first to admit that his success was unexpected. "I've been very lucky, considering what I look like and what I do," he once said. Looking back on the role that made him a household name, Gandolfini told Vanity Fair, "I thought that they would hire some good-looking guy. Not George Clooney, but some Italian George Clooney, and that would be that." He also challenged our collective belief that a criminal would be portrayed as an amoral void; instead, Tony was a surprisingly vulnerable figure, for whom murder was as much a part of daily life as feeding the family of ducks that gathered in his family pool.

The Sopranos creator David Chase saw Gandolfini as a partner and a brother, likening him to Mozart, a comparison that Gandolfini failed to see. "He was a genius," Chase said in a statement provided by HBO. "Anyone who saw him, even in the smallest of his performances knows that. He is one of the greatest actors of this or any time. A great deal of that genius resided in those sad eyes. I remember telling him many times, 'You don't get it. You're like Mozart.' There would be silence at the other end of the phone. For Deborah and Michael and Liliana, this is crushing. And it's bad for the rest of the world. He wasn't easy sometimes. But he was my partner, he was my brother in ways I can't explain and never will be able to explain."

The final episode of The Sopranos left the fate of Tony Soprano up in the air, leaving audiences wondering what was next for the mob boss as he gathered with his wife and children for a meal before the screen cut to black. It remains a much-debated (and vehemently argued) moment in television history; it is perhaps a beautiful indicator of the vagaries of life, and its mysterious unknowable quality. Life goes on for Tony Soprano, even if viewers aren't able to peer into his dark psyche on a weekly basis. Family endures, ultimately.

The character had his ups and downs with his wife, Carmela, played by Edie Falco. Gandolfini told Vanity Fair in 2012 that he still had deep feelings for his on-screen wife. "I'm still in love with Edie," he said. "Of course, I love my wife, but I'm still in love with Edie. I don't know if I'm in love with Carmela or Edie or both. I'm in love with her." In real life, Gandolfini married his second wife, Deborah Lin, in 2008 in a ceremony in Hawaii. They had a daughter, born last October, together; Gandolfini has a son, Michael, with his first wife, Marcy Wudarski, from whom he divorced in 2002.

"I am shocked and devastated by Jim's passing," said Falco. "He was a man of tremendous depth and sensitivity, with a kindness and generosity beyond words. I consider myself very lucky to have spent 10 years as his close colleague. My heart goes out to his family. As those of us in his pretend one hold on to the memories of our intense and beautiful time together. The love between Tony and Carmela was one of the greatest I've ever known."

But Tony Soprano represented a mere fragment of Gandolfini's body of work. He recently starred in HBO's Criminal Justice, an American remake of the acclaimed British miniseries that had been picked up as a limited-run series. (Tragically, Gandolfini would have been incredible in the role of Jack Stone. It was a role that he was extraordinarily suited for.) His work included such diverse films as True Romance, Get Shorty, The Taking of Pelham 123, The Juror, Crimson Tide, and The Mexican. This year, he appeared in Nicky Deuce and The Incredible Burt Wonderstone; last year found him in Oscar-nominated Osama bin Laden hunt film Zero Dark Thirty, Killing Them Softly, and Not Fade Away, where he reunited with The Sopranos creator David Chase. He lent his voice to Carol in 2009's Where the Wild Things Are. He starred on Broadway in 2009's God of Carnage, later reprising the role in a Los Angeles run and netting a Tony nomination for his role. As a producer, Gandolfini was behind such HBO war documentaries as Wartorn: 1861-2010 and Alive Day Memories: Home from Iraq; he also executive produced the 2012 HBO biopic Hemingway & Gelhorn, starring Nicole Kidman and Clive Owen.

Gandolfini will not soon be forgotten. He was, in many ways, a true Hollywood Goliath, whose performances never failed to rivet viewers and from whom it was impossible to turn away. His gaze held both power and danger, his physical presence seemed to fill the room and our collective imagination. Most tragically, it appeared as though Gandolfini was only getting started. At 51, his reign has ended far too early.