Israelites, Hebrews, Jews, whatever you call them, have been scattered and settled all over the place for thousands of years. It has become quite fashionable to discover or recognize “lost” communities. Some claim to be descended from the Ten Lost Tribes, others descendants of secret Jews who fled persecution and practiced Jewish rituals as well as non-Jewish ones. The question is whether any of them are really Jewish altogether, or if this is just a gimmick to get more people claiming Jewish ties to come to Israel.

Let’s deal with the Ten Lost Tribes first.

After King Solomon died, the Israelite kingdom split in two. The ten northern tribes became Israel, but they were also known as the descendants of Joseph. Assyria conquered the northern Israelite state in 720, took the inhabitants into exile, and scattered them around their empire. What happened to them?

Some say they were indeed lost. But ever since, all kinds of different theories have emerged as to where they ended up — from China to the Americas. There was even a Victorian organization called the British Israel Society that claimed that Britain could trace its origins back to the Ten Lost Tribes. They claimed the name “Britain” is made up of two Hebrew words, Brit and Aniya, the Covenant of Boats. There is a town in Cornwall called Marzion, which they say is also made up of two Hebrew words meaning Bitter (memories) of Zion.

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There are plenty of other claimants. The Samaritans say that they are the remnant of the Northern Tribes, who never actually left. Many Kurds also claim descent. So do some Carpathian communities. The most rational explanation of what happened to the ten tribes is this: Assyria was in turn conquered by Babylon. Babylon then conquered and exiled the southern kingdom of Judah and Benjamin in 568 BCE. Unlike the Assyrians, it allowed the exiles to form their own community and be largely self-governing. The Babylonian community became the largest Jewish community for the next thousand years and part of the Persian empire. Those Israelites who survived were then integrated into the Babylonian, Persian community.

It was in Babylon that the idea of a messianic leader who would return to rebuild the Temple emerged. This new king would be descended from the House of David. But at the same time, there would be a messiah who was related to a son of Joseph. Both ideas figure prominently in the rabbinic tradition. The fact that there were two messiahs, indicates that the House of Joseph — the Ten Northern Tribes — were still very much alive, and fought for their recognition long after the Assyrian exile.

In the ninth century, Jewish merchant Eldad Hadani claimed that he had found Israelite tribes scattered around the Middle and Far East. He himself said that he descended from the tribe of Dan, which was supposed to still live south of the River Sambatyon in central Africa. Subsequent travelers discovered Ethiopian Jews, known as the Falashas. In the 16th century, Rabbi David Ben Zimra recognized them as Jews. But since they had no knowledge of rabbinic Judaism or indeed of Hebrew, the controversy continued as to whether they were descended from Jews, or from early Christian missionaries who kept a Jewish lifestyle. Either way, most were eventually airlifted to Israel and integrated into Jewish and Israeli life.

Many groups or tribes of Jews have lived in India for a very long time. The Cochin Jews of Kerala claim descent from King Solomon. The Jews of Chennai arrived with Portuguese and Spanish traders in the 16th century. The Jews of Goa fled there to avoid the Inquisition (which pursued them there). The Benei Israel claimed to have been living in India since the first Temple times, and were influenced by the Indian caste system. The Benei Menashe claimed to be descended from the Ten Tribes, specifically the tribe of Menashe. Similarly, the Benei Ephraim also claim ancestry from the sons of Joseph and ancient Israel.

Even in Africa, the Lemba tribes observe many Jewish rituals. There is a movie, Black Jews, Juifs Noir en Afrique, which documents a dozen African tribes, in Nigeria, Ghana, Cameroon, and other countries, each with a Jewish story. Some claim to be descendants of the Ten Lost Tribes. Others believe that their ancestors were Jews who emigrated from Judea to Yemen, and then westward looking for gold. There are also ‘Judaic’ tribes in Mali, Uganda, South Africa, Zimbabwe, and Sao Tome. There are recordings widely available of many of these tribes singing Jewish liturgical songs beautifully and with expertise.

In Iberia and South America, after the Spanish and Portuguese Inquisitions started persecuting Jews, many communities fled into remote areas, where they combined Jewish customs with an outward profession of Catholicism. But they were not identified as Jews. In 1917, a mining engineer named Samuel Schwarz discovered such a community in remote Portugal that had survived in secrecy for hundreds of years by maintaining a tradition of hiding all the external signs of their Jewish faith. Some of them resumed the public practice of Judaism in the 1970s, and opened a synagogue in 1996.

The Jerusalem based Shavei Israel organization, founded in 200, literally means “The Returning Israelites.” It has helped people whose ancestors had become separated from Judaism reconnect to the faith. It sponsors rabbis and teachers to work with groups of “lost Jews,” provide them with Jewish education, and help them to move to Israel if they so choose.

We ought to be delighted that instead of Jews fleeing their Jewish identity, there are many eager to adopt or reinforce it. Yet, as usual, we are divided over the issue of who counts as a Jew and indeed whether there is any point in claiming these peoples as Jewish.

There is, of course, a political side to all this. Israel needs more Jewish immigrants to reinforce its numbers in an environment where its religion is such a sore point. Is this a legitimate “return,” or just a crude attempt to displace Palestinians and Muslims? Our enemies argue that we welcome these Jews as cover for our supposed racism towards Palestinians. Of course, Judaism is not racist. But it is interested in self-preservation. The only criterion for membership is commitment. But lies about Jews are as prolific nowadays as ever before.

For my part, I’d be happy to welcome anyone crazy enough to want to identify with us. We might not be a proselytizing religion, but that doesn’t mean we don’t welcome those sincerely wanting to join us. The question is whether, since Judaism has evolved so much over the past 2,000 years, these people who practice a pre-rabbinic form of Judaism, cut off for so long from the mainstream, need to convert, at least symbolically. And that remains one of the sticking points in Israel today, where the Chief Rabbinate is often difficult on this issue. But over time — and it does take time and goodwill — most of these peoples integrate into mainstream Jewish life.

I believe we should welcome these people with open arms. One of the reasons I so dislike religious authority is that it is, by nature, bureaucratic. And like all bureaucracies, it insists on following the letter of the law rather than the spirit. Sensitivity is not one of its great qualities.

Rabbi Jeremy Rosen has worked in the rabbinate, Jewish education, and academia for more than 40 years in Europe and the US. He currently lives in the US, where he writes, teaches, lectures, and serves as rabbi of a small community in New York.