The Porta Latina in Rome is located nearby the Terme di Caracalla and the Porta di San Sebastiano. It is named for the street of the same name and is one of the best preserved Roman gates in the Aurelian Walls.
Porta Latina Rome
History

The Porta Latina is named for the Via Latina, which led from Rome to what is now Capua, but was at the time still called Casilinum. In those days this territory was taken up by the 30 or so villages that were part of the Latin League. This was a confederation, founded to create a protection against common enemies. Initially these enemies were the Etruscans, but later they came to include the Romans. Still later Rome joined the Latin League, then took a dominant role and finally submitted the other villages. In 338 BC the organization was disbanded.
In the Republican Age (509-27 BC) the road started, together with the Old Appian Way, at the Porta Capena. The two roads separated near what is now the Piazzale di Numa Pompilio. The initial name of the street is now Via di Porta Latina. After the gate it becomes Via Latina.
Initially the opening was 6.55 metres tall and 4.20 metres wide. Between 401 and 403 Emperor Honorius had this reduced to 5.65 by 3.73 metres. The outline of the original fornix is still visible. The reduction of the wall was part of a completely restructuring to make it easier to defend the city. Honorius also had the right tower rebuilt and the travertine facade restructured.
In the middle ages the right tower was again restored.
Both in 1576 and in 1656 the gate was closed during an epidemic of the plague.
After the construction of the Via Appia Nuova the gate lost importance.
Until the early 20th century it was only open when there were special events at the San Giovanni a Porta Latina Church. Even when the Italian troops tried to enter the city here in 1870, they ended up having to give up on the attempt. Their brothers in arms at the Porta Pia ended up having more luck, though, which is why Italy now exists.
Description
The two windowless semicircular towers on each side have holes that were to be used by archers. The five openings in the upper part were created during the reign of Honorius.
The keystone of the outer arch has the Constantinian Chi Ro monogram on it. The Greek letters forming this monogram stand for Christ. To the left and right of the monogram the first and last letters of the Greek alphabet (alpha and omega) can be seen, symbolizing the beginning and the end.
The Greek cross on the inner side of the arch is also a Christian symbol.
The entrance could be closed off with a hinged gate on the inside and with a portcullis on the outside.
There is a small door behind the western door, which gives access to a walkway and a room with 17th century walls. According to legend the god Saturn hid in this chamber from his son Jupiter after the latter had dethroned him.