A description of the arch from Platner's A Topographical Dictionary of Ancient Rome describes its material and dimensions:
- "Pentelic marble, and is 13.50 metres wide, 15.40 high, and 4.75 deep. The archway is 8.30 metres high and 5.36 wide. Above it is a simple entablature, and an attic 4.40 metres in height, on which is the inscription, which is preserved only on the east side. On each side is an engaged and fluted Corinthian column, standing on a square pedestal."