A stephane (ancient Greek Στέφανος, Lat. Stephanus = wreath, decorative wreath worn on the head; crown) was a metal arc, which was like a fancy headband, higher in the center than along the sides, to be set on a female hairstyled or veiled head, which extended down behind the ears. Many of ancient Greek and Roman coins show on obverse queen's portrait wearing a veil with a stephane.
References
Stephane (Ancient Greece) Wikipedia(Text) CC BY-SA