Thessalonika was the ancient name for the modern metropolis of Thesaloniki, the second largest city in Greece. It was founded in 315 BCE by King Kassander and named for his wife, Thessalonika, who was the grand-daughter of Philip II and niece of Alexander the Great. It eventually became the most important city in Macedonia.
Interestingly, it appears that Thessalonika, despite its importance, didn’t mint any coins until Roman times. This coin is among the earliest minted there and is relatively rare. It depicts Pegasos.