Timbuktu: the name is so steeped in mystique that many people think it is an imaginary rather than a real place. Historically, the city in the republic of Mali has been a centre of Islamic civilisation in Africa. It is also home to an emerging Jewish community.
According to local lore, some of the Jewish traders who crossed the Sahara centuries ago settled there but their descendants were forcibly converted to Islam. Now a new generation wants to return to their roots and openly identify as Jews. They have taken the Hebrew name Zakhor, "remember".
The Zakhor are by no means unique. Across the continent, similar communities have been forming in Ghana, Nigeria, the Congo - there are even Tutsi Jews in Rwanda. The dramatic airlift of Ethiopian Jews to Israel, far from closing the book on black African Judaism, has led to a new chapter.
"Throughout Africa, the idea of Judaism is becoming more and more important, as is identification with Israel," says Tudor Parfitt, professor of Hebrew at London University's School of Oriental and African Studies (SOAS). "Actual practice of Judaism is also becoming more common."
Professor Parfitt has been the country's best-known pursuer of lost tribes since his book The Thirteenth Gate appeared in 1987. This weekend SOAS is hosting a conference looking at the phenomenon of the black Jewish diaspora in Africa and elsewhere. Its organiser is his SOAS colleague, Edith Bruder, the founding president of the new International Society for the Study of African Jewry and herself the author of a book on the subject.
Her paper will focus on the Igbo in Nigeria, where there are 25 synagogues across the country and about 30,000 practitioners of some form of Judaism. Like the Zakhor in Mali, the Igbo believe they are the descendants of traders who came from Israel.
African Judaism, Professor Parfitt says, has "different strands". Some groups have been influenced by the Black Hebrews, the American movement which believes the Israelites originally came from Africa. "It's a kind of Afrocentrism," he says. "At a time when not much is going very right in Africa, many of them are finding comfort and solace in this kind of identification - we are the people of Israel, we are the people of God, we are the chosen people and there is a way forward for us, everything is not despair."
While some Black Hebrews believe that other Jews are not real Jews, others are "perfectly happy to be with white Jews and do not deny their legitimacy".
Then there is the kind of example offered by the Abayudaya of Uganda, who were founded by a local chieftain Semei Kakungulu nearly a century ago. Converted to Christianity by missionaries, they read the Bible and started to take the Old Testament seriously. "They see Christians not doing it properly - eating bacon sandwiches, riding around on a bicycle on a Saturday - it doesn't seem to be consistent," explains Professor Parfitt, "They like the laws of the Tanach." So instead they adopted a form of Judaism. "It was a bit like the Khazars [in Eurasia], that kind of group conversion prompted by the recognition that there was a better way of doing things."
He himself has travelled many times to South Africa and Zimbabwe to study the Lemba whose claims of semitic descent were dramatically given credence by genetic research a decade ago. A new, and as yet unpublished, DNA study traces them not simply to the Arabian peninsula but to the Levant (which includes Palestine). In contrast, Ethiopian Jews have no such genetic links to the Middle East.
While many Lemba came to practise Christianity, there is a growing movement away from the Church. "Some of the old people in Zimbabwe who are really immersed in the original culture of the Lemba have never taken up Christianity," Professor Parfitt says. "They persisted in the practice of their original religion. That original religion, in so far as one can know very much about it, is a kind of Judaism. There's no Christianity, no Islam in it; it's a monotheistic religion with a great deal of emphasis on ritual food, circumcision - things that Jews take seriously."
He is now getting requests for ritual objects like tefilin, while here as in other places, some younger people are trying to learn Hebrew and want to go to Israel to do so.
His last book advanced the intriguing thesis that the ngoma, a 700-year old sacred drum preserved by the Buba, the Lemba priesthood (who remarkably share the so-called "Cohen gene" with other Cohanim across the globe) was in fact a replica of the Ark of the Covenant rescued from Jerusalem. He is now working on opening a Lemba museum in Zimbabwe, among other things to house the ngoma, which has not been seen since it was seized by troops earlier this year.
Overall, the take-up of Judaism in Africa is going to have "incalculable importance to Jewish people," he believes, and "not only in Africa, but also in Asia, where there are vast numbers of people who have similar views". Far from being regarded as a pariah state, Israel is "revered" among those he has visited. "They are aware of what Israel has done in Africa in aid for such a small country," he says. "Among these groups that identify with Jews, Israel is held up to be a great place. And when [Israel's] ambassadors don't pay attention to them, they get very upset."