One interesting example is the city of Salonika (now Thessaloniki) in Ottoman Greece. In 1492, the expansionist monarchs Ferdinand and Isabella (of Aragon and Castille, respectively) ordered all Jews in their kingdoms to convert, leave, or die. Those who left largely sought refuge in the Islamic World, and huge amounts went to Salonika.

Salonika was a largely Greek city at this time, but the Sephardic Jewish migration eventually became a majority. It remained a Jewish-dominated city for much of the modern era, under both Ottoman and Greek rule. However, in the midst of the first world war, a fire in the Jewish quarter devastated the community and sent many fleeing to the United States and Western Europe. A massive influx of Anatolian Jews (following ethnic cleansing attempts by Turkey and the Greek kingdom) transformed the demographics of the city, now Thessaloniki, cementing the Jews' new status as a minority in the city.

The Jewish community came to an ultimate end during the second world war, when the vast majority of the Salonikan Jews were killed by the Nazis, mostly in Polish concentration camps.

The Ethiopian Israelis. They are in the modern day state (many have immigrated to Israel proper) of Ethiopia, specifically in Aksum. Largely the Tigray and Amhara regions. As for their origin I don't feel particularly comfortable trying to explain it as it's quite, 'undetermined' with a lot of legends in place, but most revolve around the mythical king Solomons son Menelik going to the region by various means. They were largely independent in the medieval period of Europe and were only brought into the Ethiopian Empire permanently in the 17th century. Very interesting history, I believe that genetically they are not 'Hebrew' (LEvantine the word i'm looking for) at all which raises fascinating questions about how they came to adopt Judaism.

The Khanate of Khazaria is a favorite historical oddity of mine. A Steppe confederation formed in the wake of the Gokturk and Hunnic empires circa 650, they controlled the trade city of Itil in modern day Astrakhan, Russia. Finding themselves between the Christian Byzantines and the Islamic Caliphate, the Khazars chose to convert to Judaism - giving them claim to equal standing as 'people of the book' but allowing them to maintain neutrality and keep the trade routes open.

The extent of their conversion, and their lasting impact on European Jewry are controversial, and many anti-semetic conspiracy theories have formed around them. Reliable sources can be rare, but the Khazar Correspondence is a fascinating glimpse into the past.

"At length mercantile emissaries of Khorasan [a land southeast of the Caspian Sea] told me that there is a kingdom of Judah which is called al-Khazar. But I did not believe these words for I thought that they told me such things to procure my goodwill and favor. I was therefore wondering, till the ambassadors of Constantinople came [between 944 and 949] with presents and a letter from their king to our king, and I interrogated them concerning this matter, They answered me: "It is quite true, and the name of that kingdom is al-Khazar. It is a fifteen days' journey by sea from Constantinople, but by land many nations intervene between us; the name of the king now reigning is Joseph; ships sometimes come from their country to ours bringing fish, skins, and wares of every kind [The Khazars, great traders, got their wares from the Rus to the north.] The men are our confederates and are honored by us; there is communication between us by embassies and mutual gifts; they are very powerful; they maintain numerous armies with which they occasionally engage in expeditions." When I heard this report I was encouraged, my hands were strengthened, and my hope was confirmed. Thereupon I bowed down and adored the God of heaven. [Hasdai was happy: Christians could no longer say the Jews were without a country as a punishment for their rejection of Jesus.]" - Hasdai ibn Shaprut's letter to Joseph Khagan

hi all. There have been several answer attempts, but all have been removed for being overly brief (i.e. essentially just naming something) and/or consisting of Wikipedia links. Just a reminder of these two comments from the rules for answers:

A good answer will go further than a simple short sentence. As described here, "good answers aren't good just because they are right – they are good because they explain.

...

Do not just post links to other sites as an answer. This is not helpful. Please take some time to put the links in context for the person asking the question.

thx!

What immediately comes to mind is the Jewish Autonomous Oblast in the Far Eastern region of Russia.

The area was originally set up the same way the Soviet government set up other distinctly "ethnic" territories, where they could retain their cultural identity withing the greater Soviet/Socialist framework. This also was believed to help derail the Zionist movement by creating a (regulated and monitored) Jewish "homeland".

Since it was state policy to encourage Atheism, Yiddish rather than Hebrew was the national language there, and culture was expected to be expressed through the arts rather than religion.

Today, around 2% of the population in the JAO identify as Jewish.