A fascinating reverse that appears on coinage during the reign of Hadrian in the 2nd Century AD and continued under various Emperors until and including the reign of Caracalla. It still fuels, nowadays, many theories but no concrete conclusions: a link to astrology, or perhaps even a representation of an actual celestial event, a partial solar eclipse?

In a very interesting article on Coinweek, Mike Markovitz writes that "living in a world without electric lights, most ancient people were much more familiar with the night sky than we are, and the stars and planets were very important to their view of the universe. Many believed that events in the sky were closely linked to events on earth (...) Many Roman emperors took astrology seriously, some even employed court astrologers. Beginning with the first emperor, Augustus, the crescent symbol with one or more stars appears repeatedly on the coinage, probably at times when significant lunar events were observed and taken as favorable omens".