Æ21 - Philip I ΟΜΟΝΟΙΑ ΧΙΩΝ ΕΡΥΘΡΑΙΩΝ

The ΟΜΟΝΟΙΑ ("homonoia") coinage issued jointly by Erythrae and Chios reflects a formal alliance between neighboring Ionian cities, a practice that intensified under the Roman imperial system as cities competed for status and cultivated useful friendships. These homonoia issues were civic diplomacy made metal — the agreement between Erythrae and Chios was substantive enough to warrant coinage under at least two emperors.

Philip I's reign coincided with the run-up to Rome's millennial celebrations of 248 AD, a moment when provincial cities across the East were particularly active in aligning themselves with imperial favor.