Via Iconoclasm comes the news that the Toledo Museum of Art has acquired a shield portrait (Imago Clipeata) of Augustus.
These shield portraits were a popular ways to decorate buildings, from the Hellenistic period onwards being used in the intercolumnar spaces on public buildings such as bouleuteria, or placed in the pediments. The Parthenon was decorated with (real) shields by Alexander. The most famous examples of imagines clipeatae that survive, all in stone, from the period immediately before Augustus are on Delos, from the Shrine of Mithridates; from the Heroon of Leon at Calydon; and the set found in the sea off Tunisia, the Mahdia shipwreck. Mithridates had himself and his leading generals depicted in the interior of his shrine; it was destroyed by Sulla, who defeated him, soon after its creation, and this is why the heads are so well preserved.
Although the Greeks used shield portraits for deities ad mythological figures, as well as military men, the Romans preferred - given that a shield was used as part of the portrait - to restrict these sorts of images to generals, and there are many descriptions in the literary sources of Republican examples. Augustus was of course a general - though perhaps not really a Republican, despite his repeated claims to be upholding the Res Publica. Republican portraits were themselves rare, and generally produced from death masks - only the very greatest were allowed imagines, and of course during the Roman Republic the great were generally generals.
I am a little sceptical with the identification of this piece - but then smaller silver sculptures tend to be cruder than their full scale marble counterparts. It also seems a pity the size of the image is not included - though I assume that the shield is small rather than life size.
Arms and armour, both real and carved in stone, were a popular way to decorate public buildings, so featured extensively in my thesis - along with many other types of 'pretty' decoration such as garlands of flowers and cute little baby erotes (I am keen to emphasise this, as am feeling like a garçon manqué with all these posts about Marius and generals).