The chlamys is a short woolen mantle or cape of Greek origin. It consists of a square piece of cloth thrown over the left shoulder and fastened at the right shoulder or in front with a fibula (a roman clasp, brooch readily available in detector finds). Messengers like the god Hermes are often depicted wearing only the Chlamys and a large brimmed hat, the petasos. On coins with a Jupiter reverse he's usually depicted naked with a chlamys over his left shoulder i.e. not fastened at his right shoulder.