Head-shaped flasks appear in the Greek ceramic repertoire starting in the Archaic period. An fine example of Ancient Roman glass features a round body resembling two identical plump-faced heads with curly hair. The method of mould-blowing proved particularly suited to the manufacture of glass vessels of this type. The flask has been blown in a two-part mould: traces of the joining can be seen at the mid-way point, vertically, between the two faces. The double-faced figure can be identified with Roman god Janus. According to Graeco-Roman mythology and culture, Janus was one of the oldest and most important divinities. He was the god of beginnings, and usually depicted with two faces, in order to look towards both the future and the past.