Educated in Russia, Wolfgang Leonhard was sent by Moscow in 1945 to help install Stalinist socialism in the Soviet sector of defeated Germany at the outset of the Cold War. Disillusioned, he became what he called the "first dissident" of the German Democratic Republic (GDR) and, later, a historian.

In 1948, just ahead of the founding of the Soviet-style East German state, Leonhard broke with the GDR founder Walter Ulbricht and fled to Yugoslavia a year later, and, eventually, on to the newly created West Germany, where he became a linchpin for dissidents.

Leonhard's death in Germany's western Eiffel region on Sunday came after a long illness. For 21 years, until 1987, he was a professor at Yale University in the US.

Born in Vienna and originally named Vladimir, Leonhard grew up in Berlin before fleeing in 1935, during the Nazi takeover, to Moscow with his communist-inspired mother, the poet Susanne Leonhard. She ended up for 10 years in a Soviet labor camp.

As a young foreigner, Leonhard was sent for training at one of the Soviet Union's then most important ideological-political centers until 1943.

Studies in England and US

After fleeing, Leonhard studied history from 1956 at the Oxford and Columbia universities and became a sought-after expert on Russia and East Germany - and a hard critic of the Soviet system.

Leonhard's 1955 book, "Child of the Revolution," sold 600,000 copies in Germany in its original edition and was published in numerous other languages.

In it, he described his experiences within the inner circle of the German postwar communists, who at first had tried to establish what they called an "anti-fascist democracy."

Leonhard told the newspaper Die Welt in 2007 that his "eyes were opened" in 1948 during a five-hour speech in which Ulbricht had outlined his intent to set up a "bureaucratic dictatorship."

"By the summer of 1949, it became clear to me," he said. "We would become a province of the Soviet Union under Stalin. That meant I belonged to the opposition."

Leonhard shows journalists Berlin sites where he worked

Leonard said that from the 1960s he was "firmly convinced" that the Soviet system would "fall apart" in a "chain of events" that subsequently included 1968's Prague Spring and later the victory by the Solidarity trade union movement in Poland's June 1989 legislative elections.

Fascination in GDR books, articles

The historian said his particular interest in the former GDR led him to gather books and articles, notably a complete set of the newspaper Pravda at his home in the town of Manderscheid.

"My library here in Manderscheid has some 6,000 books, of which very few are about the West or the Federal Republic of Germany," Leonhard said, years after reunification. "It comprises only books about the Soviet Union, international communism - and foremost giant shelves of books about the GDR."

Leonhard also said that in western Germany prejudices against residents of the former East still prevailed and vice versa.

Ipj/mkg (dpa, Munzinger)