Porta Maggiore was really a monumental entrance built by the Emperor Claudius that also supported his aqueduct. Other aqueducts arrived here, one of the city's highest points, so water could be distributed to other areas.

Two important roads passed through the arch, the Via Prenestina and the Via Labicana. This arch was incorporated into the Aurelian walls, becoming one of Rome's gateways. It was named Porta Maggiore because it was on the pilgrim's road to Santa Maria Maggiore.
On the external side of the wall, there is a funerary monument dating back to Republican Rome. This takes the form of a baker's oven and on the frieze you can see bags of flower as well as bread being baked and sold. This was the tomb of the baker Eurisaces and his wife Atinia, found at the end of the 19th century.