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A detail of one of the panels of an ivory frieze that was found in one of the Terrace Houses at Ephesus.
Note the Roman soldiers to the left of the horse and civilians to the right of the horse. The details associated with the gear on the horse are interesting.
The frieze dates to the second century AD. It could have belonged to a lintel or some furniture. The frieze shows the Emperor Trajan and the Roman army in a victorious campaign against the Dacians (like the Column of Trajan in Rome) or the Parthians.
See here for a picture of the whole frieze.