Detail of flag.
The dark veins are visible in the marble in this detail, a feature characteristic of Luna marble but also a number of other white marbles used in Rome in the second century AD. Compared to the ceremonial scenes in the panels on the Arch of Trajan at Benevento, the Antonine panels on the Arch of Constantine have much more detailed backgrounds - there is a attention to providing an architectural setting for the scene being depicted.
