Robert Hughes, the eloquent, combative art critic and historian who lived with operatic flair and wrote with a sense of authority that owed more to Zola or Ruskin than to his own century, died on Monday at Calvary Hospital in the Bronx. He was 74 and had lived for many years in Briarcliff Manor, N.Y.

He died after a long illness, said his wife, Doris Downes.

With a Hemingwayesque build and the distinctively rounded vowels of his native Australia, Mr. Hughes became as familiar a presence on television as he was in print, over three decades for Time magazine, where he was chief art critic and often a traditionalist scourge during an era when art movements fractured into unrecognizability.

“The Shock of the New,” his eight-part documentary about the development of modernism from the Impressionists through Warhol, was seen by more than 25 million viewers when it ran first on BBC and then on PBS, and the book that Mr. Hughes spun off from it, described as a “stunning critical performance” by Louis Menand of The New Yorker, was hugely popular. In 1997, the writer Robert S. Boynton described him as “the most famous art critic in the world.”

It was decidedly not Mr. Hughes’s method to take prisoners. He was as damning about artists who fell short of his expectations as he was ecstatic about those who met them, and his prose seemed to reach only loftier heights when he was angry. As early as 1993, he described the work of Jeff Koons as “so overexposed that it loses nothing in reproduction and gains nothing in the original.”

“Koons is the baby to Andy Warhol’s Rosemary,” he summarized, adding: “He has done for narcissism what Michael Milken did for the junk bond.”

Of Warhol himself, the most influential artist of the last 40 years, he was not wholly dismissive — he once referred to him as “Genet in paint” — and he softened in his judgment over time. But he argued that Warhol had only a handful of good years and that his corrosive shadow over contemporary art ultimately did more harm than good. “The alienation of the artist, of which one heard so much talk a few years ago,” he wrote in 1975, “no longer exists for Warhol: his ideal society has crystallized round him and learned to love his entropy.”