The brilliance of gold, its intrinsic value and connotations of immortality,
made gold, and to a certain extent silver a treasured material for
portraiture. Literary sources inform us that different emperors rejected
the erection of their images in gold because it implied divine honours.
In his Res Gestae Augustus records that he had 80 statues of himself in
silver melted down for better purposes. These examples demonstrate that
gold and silver were materials which had connotations of immortality
and extravagance and which the emperor used or accepted only cautiously.
Some of the images in gold representing the emperor were
certainly life-size or even colossal but most may have been of small scale or in the bust format.
The only two preserved portrait images of gold are busts and represent the almost life-sized bust of Marcus Aureliusfrom Aventicum and the approximately half life-size bust of SeptimiusSeverus from Plotinopolis.Both busts were found in areas where the Roman army had a strong presence and it has been convincingly argued that the gold busts as well as a large silver bust of Lucius Verus from the Marengo treasure found near Torino in Northern Italy served a very specific purpose: mounted on standard poles, they were taken on campaign by the Roman army. The busts could easily
be carried around and all three show the emperor in the same type of
scale cuirass. This was perhaps a cuirass more suitable to campaigns than
the anatomical cuirass ornamented in relief with figural decoration. It
indicates a common purpose for all three busts. The standards were the
pride of the Roman army. They were guarded and kept in a shrine, sacellum,
in the middle of the camp when not in use and it was to the
imagines of the emperor on standards that soldiers swore their oath.
Images in gold seem to have been an imperial privilege although epigraphic
evidence from the eastern part of the Empire shows that they
were awarded to private benefactors at least until the Early Empire.
Such examples of private citizens being honoured with portraits in gold are,
exceptions however. They no doubt represent a continuation of the type
of images set up to Hellenistic rulers and their families, a tradition which
quickly disappeared during the Early Empire.
Silver was a material commonly used for imperial portraits. However
it is often impossible to determine which format they were executed in
from inscriptions. An inscription from Ephesos, for example, records a
letter from Marcus Aurelius and Lucius Verus to the gerusia (council).
The emperors are replying to a request made by the gerusia to be allowed
to melt down some old and worn silver images of previous emperors
into images of the new emperors. It is replied that the old images
should be preserved, and that the inscriptions would help re-identify
them. The Greek term used for the images is eikon, which could mean
either bust or statue. A series of inscriptions from Ostia, dedicated by
members of the traiectus rusticelii mentions a special type of silver image
of the Roman emperor, a clipeus carried by an Atlante in bronze. Likewise
in Ostia, the collegium of cannofori dedicated silver images of the
Antonine and Severan imperial family, of which only the small bases
have survived. Silver and bronze covered with thick silver foil were
certainly also used for private portraits but whether these were only displayed in a private context remains uncertain.
In municipal towns the most desired material for honorific statues of
private citizens was gilded bronze. Inscriptions demonstrate that a gilded
statue was awarded to especially deserving citizens – probably most often in the pose of an equestrian statue. In the epigraphic material
compiled by Forbis, only three statues are mentioned to be of gilded
bronze and two of them are specified as being equestrian. According to
Lahusen only ten of the preserved bronze portraits with remains of
gilding, dating from the end of the Republic and into Late Antiquity,
are to be identified with imperial persons. Gilding was an expensive
technique during the Early Empire, as relatively thick leaves of gold had
to be used. This technique was replaced sometime during the first century
A.D. by much cheaper leaf gilding.
Ivory is briefly mentioned below as a material exploited for miniature
portraits. Literary sources, however, suggest that it was also
used for full-size statuary (as acroliths in combination with gold?) to
stress royalty because of the parallels with the practices of the Hellenistic
kings. After his victory in 45 at Thapsus, Julius Caesar was awarded
a statue in ivory to be carried in procession.