Medusa was a popular symbol on ancient Greek coins, particularly in regions like Sicily, Thessaly, and the Peloponnesus. 
Her image was not just for decoration, it carried deep symbolic meaning tied to protection, power, and divine association.
Medusa is indeed one of my favorite subjects, it amazes me how after 2400 years its image keeps a powerful energy.
Silver Obol circa 4th century BC
Pisidia Selge
Obv : Head of Medusa facing , Rev Goddess Athena