Mr. Heaney (pronounced HEE-nee), who had made his home in Dublin since the 1970s, was known to a wide public for the profuse white hair and stentorian voice that befit his calling. He held lectureships at some of the world’s foremost universities, including Harvard, where, starting in the 1980s, he taught regularly for many years; Oxford; and the University of California, Berkeley.

As the trade magazine Publishers Weekly observed in 1995, Mr. Heaney “has an aura, if not a star power, shared by few contemporary poets, emanating as much from his leonine features and unpompous sense of civic responsibility as from the immediate accessibility of his lines.”

Throughout his work, Mr. Heaney was consumed with morality. In his hands, a peat bog is not merely an emblematic feature of the Irish landscape; it is also a spiritual quagmire, evoking the deep ethical conundrums that have long pervaded the place.

“Yeats, despite being quite well known, despite his public role, actually didn’t have anything like the celebrity or, frankly, the ability to touch the people in the way that Seamus did,” Mr. Muldoon, a winner of the Pulitzer Prize and the poetry editor at The New Yorker, said in an interview on Friday. “It was almost like he was indistinguishable from the country. He was like a rock star who also happened to be a poet.”

Mr. Heaney was enraptured, as he once put it, by “words as bearers of history and mystery.” His poetry, which had an epiphanic quality, was suffused with references to pre-Christian myth — Celtic, of course, but also that of ancient Greece. His style, linguistically dazzling, was nonetheless lacking in the obscurity that can attend poetic pyrotechnics.