Castra Praetoria

The Castra Praetoria was the Barracks of the Praetorian Guard in Rome built by Tiberius in 23 CE.
It was located to the northeast of Rome outside the Servian Wall.

The original Walls run along the Viale del Polyclinico.
- The Metro station and city district are both named Castra Praetorio.
- Sections of three of the four walls of the Castra Praetorio are still standing today, as they were incorporated into the Aurelian Walls.
- However, the interior was demolished by Constantine I in 312 CE and is now occupied by modern buildings.
The Porta Praetoriana (Praetorian Gate)
- This is a walled up gate that is visible opposite 129 Viale del Polyclinico.
The northeastern corner Tower
- This is visible from the Piazza Girolamo Fabrizio.

The Castra Praetoria was the first building to use Opus Recticulatum, using concrete walls faced with Tuff.
The walls of the Castra were incorporated into the later Aurelian Walls between 270-275 CE.
It was eventually demolished by Constantine I in 312 CE.

It was built in the shape of a rectangle with 16 towers which did not extend beyond the wall.
It probably had a gate on each side, although only the North and East Gate remain.
There was no ditch surrounding it.
The walls were built using Opus Recticulatum, which was Roman concrete, Opus Caementicium, filled with stones and then faced with brick or a volcanic stone called Tuff, producing a pattern.
It was one of the first structures to be built this way.
The interior of the walls supported a series of arches that supported a walkway along the top, and living quarters below.

Excavations have revealed that the interior was not based on the layout of the standard legionary fort.
The Fort was divided into five zones by four horizontal avenues across the north south axis.
Two rows of barracks extended from wall to wall.
Another two rows of very unusual two storey barracks are located in front of the east gate.
One estimate for the number of soldiers housed in the Castra is between 5,000 and 15,000.
No evidence of a Principium, Commanding Officer’s quarters, have been identified. This would suggest that the Praefectus Praetorio lived in the Imperial Palace, and conducted business from there.

Porta Praetoriana, Castra Praetoria