Peter R. Viereck, 89, a historian, Pulitzer Prize-winning poet and political philosopher who was spurned by the modern conservative movement despite his central role in its birth, died May 13 at his home in South Hadley, Mass. The cause of death was not reported.

Mr. Viereck was the author of nine volumes of poetry, including "Terror and Decorum: Poems 1940-1948," which won a Pulitzer Prize in 1949. A professor of history who taught at Mount Holyoke College in Massachusetts for 50 years, he was close to Joseph Brodsky, the Nobel Prize-winning Russian poet, who considered Mr. Viereck "perhaps the greatest rhymer" of the modern era.

Mr. Viereck also was a political thinker, whose provocative 1949 book, "Conservatism Revisited: The Revolt Against Revolt," defined the modern conservative movement.

"This was the book which, more than any other of the early postwar era, created the new conservatism as a self-conscious intellectual force," historian George H. Nash wrote in his 1976 book, "The Conservative Intellectual Movement in America."

"It was this book which boldly used the word 'conservatism' in its title -- the first such book after 1945," Nash wrote. "At least as much as any of his contemporaries, Peter Viereck popularized the term 'conservative' and gave the nascent movement its label."

Last year, Mr. Viereck was featured in a New Yorker magazine profile that renewed interest in his political writing from the 1940s and 1950s.

The October article by Tom Reiss provoked heated reaction from the mainline conservative journal National Review.

"The true story is that Viereck was on stage during the creation of modern conservatism, but only in the opening scene," National Review political reporter John J. Miller wrote. "Then he walked away, never to be heard from again, except occasionally as a heckler."

Mr. Viereck, who was born in New York in 1916, was the eldest of two sons of George Sylvester Viereck, a poet and journalist who interviewed Adolf Hitler and became known as a Nazi propagandist. He was convicted in 1941 of conspiring with the Nazis and spent four years in federal prison.

Mr. Viereck, then in graduate studies at Harvard (where he earned a bachelor's, master's and, in 1942, PhD in history), found his father's activities repugnant and broke off relations for the next 16 years.

He spent World War II writing intelligence reports in Africa and Italy for the Army's psychological warfare branch. He was also writing poems, several of which were published in the New Yorker.

After the war, Mr. Viereck married a Russian resistance fighter, Anya de Markov, whom he married and divorced twice. She died in 1972. He is survived by two children from that marriage; his second wife, Betty Falkenberg Viereck; three grandchildren; and a great-grandson.

In 1949, Mr. Viereck set the intellectual foundation for conservatism in "Conservatism Revisited."

"The conservative principles par excellence," he wrote, "are proportion and measure; self-expression through self-restraint." He opposed political extremism and was both an anti-communist and an opponent of Sen. Joseph McCarthy. He supported Adlai Stevenson for president.

In the 1960s, Mr. Viereck turned away from politics and focused on teaching history and writing poetry. He was believed to be the only American to win Guggenheim fellowships in both history and poetry.