Thrace, Byzantion. Alliance coinage with Kalchedon, late 3rd-2nd century BC. Æ (28mm, 9.11g, 12h). Wreathed and veiled head of Demeter r. R/ Poseidon seated r., holding aphlaston and trident; monogram to inner r. Schönert-Geiss, Byzantion 1271-5; HGC 3, 1428. Roughness, VF