One of the gates is formed by the quadrifrontal arch of Caracalla, a rare form of construction.
Under the constitution of Caracalla (198-217) all inhabitants of the Roman empire enjoyed the civil rights of the Cives Romani (Scherer, Die Rechtsverhaltnisse der Juden, p. Io).
A road, the Via Ardeatina, led to Ardea direct from Rome; the gate by which it left the Servian wall was the Porta Naevia; a large tomb behind the baths of Caracalla lay on its course.
The emperor Caracalla, wishing to make use of this civil war for a conquest of the East in imitation of his idol, Alexander the Great, attacked the Parthians in 216.
If the author or promoter of the work is one of the emperors, it is most likely to be Antoninus Caracalla.