The Egyptian motifs of the figured decoration suggest the vessel's origin. The cut decoration includes a man carving the Greek numeral 7 (the letter zeta) on a Nilometer, a device used to measure the water-level of the Nile's annual flood. It is shown here as a round-topped column. On the other side a female, probably the Egyptian goddess Isis, reclines, her left elbow resting on a pile of stones. To her right is a building on a podium. The cup belongs to a distinctive series of cut glass vessels with similar styles of cutting, engraving and lettering. Complete examples generally come from the western provinces of the Roman Empire, but fragments are known from eastern sites, including Karanis in Egypt and Dura Europus in Syria. The inscriptions, when they occur, are always in Greek, which remained the common language and script in Egypt and the eastern provinces in the Roman period. From the end of the first until the fourth century AD, intentionally coloured glass was rarely used, apart from a mould-blown series that seems to have been a speciality of the glassmakers at Cologne. Colourless, that is clear, glass came to be used for the finest or most luxurious pieces like the cut series. Natural greenish and bluish-green glass was used for mass-produced objects for everyday use.