In Lombard times, it was incorporated into the southern sector of the city walls and became known as Porta Aurea ("Golden Gate").
The arch was studied by Sebastiano Serlio in Renaissance times and drawn by Giovanni Battista Piranesi in the 18th century.
It was restored several times due to aging and earthquakes: under Pope Urban VIII, then in 1661, 1713 (after the marble architrave crumbled) and 1792.
They are separated by narrower decorative panels depicting Victories offering sacrifices of bulls in the center and Amazons at the top.
The internal façade of the archway has two wide sculpted panels, portraying scenes of Trajan in Benevento: on the left (from inside the city) is the Sacrifice for the opening of the Via Traiana, with the emperor flanked by lictors, while on the right is the institution of the alimenta (a beneficent institution created by Trajan to help children in Roman Italy), symbolized by pieces of bread on the table in the center, with personifications of Italian cities with children.