PRINCETON, N.J. – Diplomat and Pulitzer Prize-winning historian George Kennan, who gave the name “containment” to postwar foreign policy in a famous but anonymous article, died last night at his Princeton home, his son-in-law said. Kennan was 101.

Identified only as “X,” Kennan laid out the general lines of the containment policy in the journal “Foreign Affairs” in 1947, when he was chief of the State Department’s policy planning staff. The article also predicted the collapse of Soviet Communism decades later.

When the Communist Party was finally driven from power in the Soviet Union after the failed hardline coup in August 1991, Kennan called it “a turning point of the most momentous historical significance.”

In his 1947 article, Kennan disagreed with the emphasis on military containment embodied in the “Truman doctrine.” That policy, announced three months before publication of Kennan’s article, committed American aid in support of “free people who are resisting attempted subjugation by armed minorities or by outside pressure.”

Despite the “X” article and his work in formulating the Marshall Plan, Kennan lost influence rapidly after Dean Acheson was appointed secretary of state in 1949. During his years out of the foreign service, Kennan won the Pulitzer Prize for history and a National Book Award for “Russia Leaves the War,” published in 1956.

He again won the Pulitzer Prize in 1967 for “Memoirs, 1925-1950.” A second volume, taking his reminiscences up to 1963, appeared in 1972. Among his other books was “Sketches from a Life,” published in 1989.