Demetrias was founded in 294 BCE by Demetrios I Poliorketes, who forcibly moved the inhabitants of a number of other surrounding cities, to create a city in his namesake. This was all the rage back then and each king sought to have his very own namesake city. A few renamed existing cities, but many had to create shiny new ones.
After Demetrios, most of the Macedonian Kings spent a lot of time here. However, this relatively rare triobol was minted most likely while Demetrios was still alive, and bears a style similar to his other coins of the day – with a prow.
Artemis, who is pictured on the obverse of this coin, was also depicted on earlier coinage from Rhizous, which was displaced by Demetrios to create his city.