James Gandolfini, who rose to fame as the agonized mob boss on HBO's groundbreaking drama "The Sopranos," has died, the network confirmed late Wednesday.

FULL OBITUARY: James Gandolfini brought swagger, genius to 'The Sopranos'

Gandolfini, who was 51, was stricken during a stay in Italy, according to reports. The cause of death was not immediately known but was initially attributed to either a heart attack or stroke.

On "The Sopranos," Gandolfini played New Jersey crime boss Tony Soprano, who alternated acts of mayhem with a visits to his psychiatrist.

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Twitter: @scottcollinsLAT