The art of engraving gemstones can be traced back to ancient Greece in the 8th century BC and earlier. Techniques passed down to the Egyptians and then to the Romans. There were major revivals of interest in engraved gems in Europe during the Byantine era, the Middle Ages, the Renaissance, and again in the 18th and 19th centuries. At each stage cameos and intaglios, these skillful carvings on a minute scale, were much prized and collected, sometimes as symbols of power mounted in jewelled settings, sometimes as small objects for private devotion or enjoyment. This gem is in the neo-classical style popular in the late 1700s and early 1800s, when taste in the arts echoed the subject matter and style of the Greek and Roman masters. Thousands of gems were made in this style in Italy and brought back by British Grand Tourists, who went there to visit the newly-discovered classical antiquities and archaeological sites. It portrays the Roman god Jupiter in a particular guise known as Jupiter Ammon. After the Roman conquest of Egypt, the Roman god Jupiter acquired some of the attributes of the Egyptian deity Amun, and was sometimes shown with horns. Amun in turn had descended from an earlier north African god who took the form of a ram, and was associated with the protection of the flock and fecundity. The appearance of this cameo, with its striking use of coloured layers, may have been artificially enhanced by the use of staining.