Tritartemorion

Massalia — the Greek colony at modern Marseille — was one of the most prolific mint cities of the ancient western Mediterranean, and its fractional silver coinage circulated extensively through trade networks reaching deep into Celtic Gaul. The tritartemorion, worth three-quarters of an obol, served the fine-grained commercial arithmetic of a busy port economy where smaller fractions mattered.

At roughly half a gram, these pieces were struck on tiny flans prone to off-center placement, and fully centered examples are genuinely scarce.