by Giuseppe Agostino Pietro Vasi, 1747

It consists of a single large arch built for Pope Gregory XIII, perhaps by Giacomo della Porta or, as some maintain, by Giacomo del Duca, who had worked with Michelangelo on Porta Pia. The confusion arises because the chronicles of the time simply speak of a famous architect called Giacomo. Popular tradition has it that the architect was Della Porta, since he died in the crowd in front of the gate "he had built" of violent indigestion brought on by melons and watermelons, on his way back from a trip to the Castelli Romani.

Inaugurated in 1574, it was made necessary by the reorganisation of the whole Lateran area to ease traffic to and from southern Italy. Its opening led to the definitive closure of the nearby and more imposing Porta Asinaria, of Aurelian date, which already in the 1570s was proving unable to cope with such heavy traffic and was almost unusable owing to the gradual raising of the surrounding street level.