What is the historical significance of Thessaloniki, Greece?

Up and coming city in the Roman Empire. Was the base of the Emperor Galerius. Very important city during Byzantium, to the extent of being termed the Co-Queen of Cities (συμβασιλεύουσα—the Queen of Cities being Constantinople). Main trading town for much of the Balkans. Major centre of Sephardic settlement after their expulsion from Spain—to the extent of being a largely Jewish city until the 20th century, and an inspiration to Zionists. Lots of historical architecture spanning a very long period. Having been the Co-Queen of Byzantium, is now the Co-Capital of Greece (συμπρωτεύουσα). Has traditionally been the refuge of progressive intellectuals, though commentators have noted that the dust of reaction has settled around it more recently.