Æ17 ΕΡΜΟϹ, countermark

The countermark here is the point of interest. Howgego 354 is an oval punch bearing the name ΕΡΜΟϹ — the river Hermos, which flows through the Lydian plain past Magnesia ad Sipylum itself. Civic countermarks of this type were applied to existing bronze coinage to revalidate or recirculate it, typically when a fresh issue was either unavailable or administratively inconvenient. The host coin's original type becomes secondary; the city was essentially endorsing the bronze rather than replacing it.