Though the premature death of Professor Rashid Muradovich Kaplanov was a shock to the world of Jewish studies, it was not altogether surprising given his girth and sedentary habits, derived from a life spent largely in the Reading Room of the Lenin Library in Moscow.

Kaplanov carried many mysteries to the grave. What is certain is that he was one of the world's great polyglots — a scruffy, unworldly, lovable man with a prodigious memory and a mastery of 36 languages, including some of the hardest, such as Hungarian (of which his knowledge extended to regional dialects), and some of the most obscure (such as Mirandese, spoken in a small area of northern Portugal).

A longstanding member of the Russian Academy of Sciences' department of general history, he was the first Russian citizen to preside over the European Association for Jewish Studies and did much to re-establish Jewish learning, secular and religious, as a subject of teaching and research in Eastern Europe after the collapse of the Soviet Union.

Rashid Muradovich Kaplanov was born in Moscow in 1949. His grandfather and namesake was Prince of the Kumyks, a tribe of some 200,000 Muslims in the mountains of Dagestan. This remote Russian territory extends from Chechnya to the Caspian Sea. According to tradition, the Kumyk princes are direct descendants of Muhammad; the Kumyks also are said to derive from a lost tribe of Jews — the Khazars.

His grandfather, Prince Rashidkhan Khan Kaplanov, had a Jewish wife and was a leader of the short-lived government of the Caucasus during the Russian Revolution. Under the Soviet Union, Kaplanov's father was imprisoned for five years as the son of Prince Rashidkhan, by then designated an enemy of the people. But he then became prominent in the space programme and was the chief designer of the radio rebroadcast system for the Molniya communications satellites. The satellites had military as well as civilian functions. He was responsible for developing the communication systems from military units to the centre and Molniya's on-board re-transmitter. Because of this work his son was not permitted to travel out of the Soviet Union until after his death in the 1980s.

Kaplanov's mother was also Jewish, which meant that, according to Jewish law, he was a fully-fledged Jew. Though never observant, he became increasingly involved in the 1990s in the revival of Jewish studies in the countries of the former Soviet empire.

After suffering from polio at the age of five, he graduated in history in 1971 at Moscow State University, and then carried out doctoral research from 1971 to 1974 at the Institute of World History of the Russian Academy of Sciences. His thesis was on “The political system of Portugal, 1945-74”.

There could hardly have been a more sensitive subject. After the military coup of April 1974 against the Salazar-Caetano regime, one of the decisive contests of the Cold War was taking place in Portugal. Amid the Portuguese revolution, the Soviet Union and the West carried out rival secret operations to fund emerging political parties and so win the allegiance of Portugal and its African possessions.

The electoral victory in 1975 of Portugal's Social Democrats over Alvaro Cunhal's Communists led in turn to the Communist defeat in post-Franco Spain. These events arguably did much to produce the overall defeat of the Soviet Union in the Cold War.

In contrast to his policy-relevant work and the propagandist publications he was obliged to write on contemporary Iberian and Latin American society and politics, Kaplanov embarked on research into the Sephardic (Spanish and Portuguese) Jews who had lived in Moscow after their expulsion from the Iberian peninsula between 1492 and 1497.

Among his exotic interests were topics such as the history of the Karaites (a Jewish sect in the Black Sea region), the Karaims (another sect of Jewish origin in Lithuania), the Sorbians (a Slavic group in east Germany), the conversion to the Russian Orthodox church of Sephardic Jews in 18th-century Moscow, the career of Antonio Ribeira Sanches, a Portuguese-Jewish physician to the Russian court whom he named “the first Jewish intellectual in Russia”, and the Karaite pronunciation of Hebrew.

It is easy to speculate that Kaplanov was attracted to these subjects because they were safer than Cold War politics. When asked by a Portuguese scholar why he had become fluent in Basque, he replied that the KGB was unlikely to have a censor able to read his letters in that language.

Politics apart, he was genuinely fascinated by topics that required the knowledge of many languages and obscure facts, and which allowed him to bury himself in Russia's greatest library. His background led him to identify with the languages and cultures of lost and endangered tribes and, by studying them, to preserve their memory.

The relative freedom enjoyed by Jews in the former Soviet satellites and in the successor states to the Soviet Union after the fall of communism led to mass emigration and to a struggle (according to the title of one of his works published in 1998) between assimilation and resurgence. Kaplanov devoted the last 16 years of his life to the intellectual resurgence of Jewish culture among the remnants of communities almost destroyed by the Nazis and the Communists.

It was an uphill task. Kaplanov and the academics surrounding him were constantly short of funds. Outside Moscow, where the relationships between different institutions teaching Jewish studies were cordial, there was the all too usual academic faction-fighting, especially in St Petersburg and in Kiev. Kaplanov's sense of humour, love of conversation, brilliance as a lecturer and intellectual virtuosity made him into an improbably successful public figure and diplomat.

From the 1990s his new political freedom led to a rush of varied publications on non-Jewish and Jewish subjects, which appeared in Polish, Yiddish and Spanish as well as in Russian. He wrote on Guizot and Ortega y Gasset, on the origins of Basque and Catalan nationalism, and on Jewish topics.

Apart from his teaching at the new Moscow Jewish University (where he became a professor and head of the department of modern Jewish history), he was a founder in 1994 and academic director of Sepher (Book), an organisation set up to promote teaching in Jewish civilisation in universities in Russia and its neighbours, which brought together academics specialising in Jewish studies from far-flung universities.

The success of Sepher and of Kaplanov's appearances at conferences in Bulgaria, the Czech Republic, Germany, Israel, Italy, Portugal, Poland, Spain, Ukraine, the UK and the US led to his election in 2002 as president of the European Association of Jewish Studies. This was a personal honour and recognition of the revival of Jewish culture in Eastern Europe which he had done so much to promote. In 2002-06 he embarked on an exhausting series of visits to Jewish communities throughout the former Soviet empire.

Proud of his Muslim as well as his Jewish roots, Kaplanov was saddened that he did not marry or produce an heir, which meant that he was the last of the Kumyk princes.

Professor Rashid Kaplanov, historian and president of the European Association of Jewish Studies, was born on January 19, 1949. He died on November 27, 2007, aged 58