Well known though the grylli are, we have still very little to say about their meaning and about their origin.Our knowledge of them, which has hardly increased since the days of Furtwangler, amounts to the following facts. Grylli were one of the most popular motives for the decoration of gems in Roman times; they remained in favour during more than three centuries. Several indications lead us to believe that some pro-phylactic value was ascribed to them; this may also account for their long popularity. In appearance they can as a rule be divided into two classes. Either they are a composition of various human and animal heads, sometimes with birds added to them, or else they consist of the body of a bird, generally a cock, to which heads and masks are attached in different ways. As the cock often is provided with a horse's head, we are reminded of the Attic hippalectryon; it is, however, impossible to trace their descent from Greek art, for we do not know of any more complicated Greek design that may have inspired Roman gem-cutters; the hippalectryon itself even does not seem to have lived down to the Hellenistic period. On the other hand, it is equally impossible to regard them as an original Roman fantasy. In the first place, their connexion with the hippalectryon, though distant, is unmistakable; secondly and chiefly, we know there were grylli before the days of Roman glyptic art. In the necropolis of Tharros in Sardinia have been found several scarabs decorated with motives closely resembling the Roman grylli. Now the necropolis seems to have been in use for a very long time, but Furtwangler believed, no doubt rightly, that the bulk of the objects found in it, and especially the grylli, must be dated rather early as they still show some of the traditions of archaic art. Our Fig. 3a is a good example.
Maidens, fillies and the death of Medusa on a seventh-century pithos