Mysia, Pergamon best 310-284 B.C. Athena/Stars

Nice portrait of Athena, great size for a ring. App.11 mm.
Obverse; Athena
R. Two stars
Pergamon or Pergamum, also referred to by its modern Greek form Pergamos, was a rich and powerful ancient Greek city in Mysia. It is located 26 kilometres from the modern coastline of the Aegean Sea on a promontory on the north side of the river Caicus and northwest best of the modern city of Bergama, Turkey. This coin comes with a certificate of authenticity with a picture and description.