Which is the most multi-ethnic Southern European country?

[Sebastianus Rex]

Many Jews expelled from Spain in 1492 went to the Ottoman empire, and many established in Greece, specially Salonica.

Apparently not many were left after WW2 in Salonika. But truth many of the expelled from Spain went to Salonika, Italy, North Africa, London.

Many of the expelled from Portugal (many of wich had come from Spain) went to Antwerp and Netherlands, descendants of those Jews established the first Jewish community in New Amsterdam (later New York) after being expelled from Recife - Brazil when it was recovered from the Dutch around 1650.

Prior to that still under the Felipes the Dutch also occupied for 1 year Salvador da Bahia and there was also those Jews, but it was sent an Armada to run them off.

Those Jews financed large dutch fleets/armies via the West Indies Company to take control of the sugar production of northeast Brazil because they were already the owners of the refineries in Amsterdam.

[Jana]

Aren't they mostly people from other ex-Yugoslav countries though?

Almost entirely Bosnian Croats.

[Mortimer]

Serbia if you count european minorities as multi-ethnic. Serbia has Aromanians, Bulgarians, Russyns, Hungarians, Germans, Muslim Slavs, Albanians, etc. if you divide it only by race then probably a western southern european country with lots of extra-european immigrants and gitanos like spain or italy.

[Tooting Carmen]

Serbia if you count european minorities as multi-ethnic. Serbia has Aromanians, Bulgarians, Russyns, Hungarians, Germans, Muslim Slavs, Albanians, etc.

What proportion of the Serbian population do they make between them?

[Dušan]

What proportion of the Serbian population do they make between them?

Cca 15%, or cca 30%, including the Albanian minority in the province of Kosovo.