Mithraeum of the Baths of Caracalla

TNMM 16 ↔ CIMRM 457

Originally discovered in 1912, this mithraeum is considered the largest documented gathering space for the worshippers of Mithras. The mithraeum, approximately 23 meters long and 10 meters wide with a soaring cross-vaulted ceiling, can be only roughly dated by the two main events associated with the bath complex: the mithraeum was certainly created after the complex was completed in AD 217, and it was probably no longer in use when the aqueduct supplying the complex was cut during the Greco-Gothic Wars in 537. In reality, it probably went out of use long before 537, since most scholars hold that Christianity had supplanted Mithraism as a “religion for the masses” by the early 4th century.

Today, a visit to the mithraeum can be considered a brief one, as what is available to us are primarily two chambers: a small square ante-chamber and the main rectangular meeting hall. Apart from a recently-restored fresco of the god (missing the face, unfortunately – presumably hacked away by Christians), there is very little left of the decoration, which was probably very lavish. The well-preserved podium structures on either long side, on which the worshippers reclined during ritual meals, give an excellent idea of the context and purpose of the shrine. Certainly the most intriguing feature is the small tunnel that runs under the center of the main hall into an adjoining room, where there is an entrance/exit with staircase; this has been identified with some controversy as the fossa sanguinis, the ritual pit over which the bull at the center of the Mithraic mythology was slaughtered, bathing one or more initiates in its blood.

Its location, off a dirt road adjacent to the main entrance, is part of a subterranean area of the Baths of Caracalla. The mithraeum space is just one part of the massive, sprawling system of underground corridors that honeycombs the large artificial platform supporting the Baths of Caracalla. Beneath the thermae complex lies a warren of tunnels with furnaces, stoked by slaves, and storage areas for supplies, including wood. Though access to these tunnels is today only partial, there are confirmed plans to extend the conservation and restoration work to make more of these areas accessible, including a substantial area dedicated to grinding grain using the water that passed through the baths.

Under the Southern part of the Northern gallery of the Caracalla-therms, a Mithraeum was discovered in 1912.

By entrance g (Br. 1.75) with a marble threshold, one enters the sanctuary (L. 23.00 Br. 9.70). It is divided into a central aisle (Br. 4.65) covered with black and white mosaic, and two benches sloping towards the side-walls. The right bench (H. 1.00 Br. 2.17 L. 19.17) begins at some distance (1.45) from the entrance and ends at 1.70 from the back-wall. Here (8) it is accessible via two steps (Br. 0.70). An edge (Br. 0.40) covered with marble slabs runs all along the front. The left bench has approximately the same sizes and construction. It has, just as the other bench, two small niches (IO) in the raised front. Of these niches the one (H. 0.46 Diam. 0.56 D. 0.45) is at the beginning of the benches, the other (H. 0.51 Diam. 0.80 D. 0.60) approximately in the middle. Tall brick-pillars stand on the benches, supporting the vaulted roof. They were covered with marble on that side, which was visible from the central aisle. Through these pillars narrow passages (H. 2.00) have been made, which make it easier to go from one side of the bench to the other. Remarkable is the fact, that on the r. bench the first passage is bricked up and that instead an oblong opening (H. 0.70 Br. 0.40-0.20) is found.

In the floor of the central aisle just behind the entrance, there is a round hole (diam. 0.93 D. 0.95) covered with a stone lid (I). Next, there is near the middle (see 2) an oblong rim (L. 1.85 Br. 1.70) in which a large opening (L. 1.35 Br. 1.00) has been hewn out, which by an underground passage communicates with one of the side-rooms of the sanctuary. Then there is a third square opening (3) (L. 1.00 Br. 1.00) and finally in front of the niche another hole (4) (L. 0.30 Br. 0.30), communicating with a canal, which disappears into the r. bench.

The central aisle leads to an arched and cave-like cult-niche (H. 1.30 Br. 3.56), which is accessible on either side (6) by four steps. In the fourth step on the r.h. side, there is a small hollow, in which probably a lamp was placed. Before the niche in the central aisle, a triangular base with the top towards the entrance (Br. 0.87). Before the entrance, there is another room (L. 9.30 Br. 4.80), which is divided into two parts. From the first narrow appartment (L. 3.35) one can enter the left part of the sanctuary by an entrance (u) (Br. 1. 18) with a marble threshold. Left of the entrance I of the other room (L. 5.95) there is a spacious deep basin, with four steps leading into it.

Alongside the sanctuary there is a series of apartments of which it cannot be said with certainty if they communicated with the Mithraeum. Room y behind entrance e was indeed used as a passage to the sanctuary. In the back-wall of this oblong room there was an half-round water-basin (Br. 1.40). By i one enters another large room (n); in which two smaller rooms (l and m) served as lavatories. They are separated by a passage, which underground leads to an oblong opening (2) in the floor of the actual sanctuary. One descends into this passage via three steps. Entrance 0 finally leads into the last room (L. 8.85 Br. 5.50), in which against the back-wall a kind of counter (H. 1.00 Br. 0.75) has been built with four semi-circular niches under it. In the floor is a round pit (Diam. 1.50 D. 0.64), into which one can descend by two narrow steps on two sides. On a line with this pit, there is in the wall on the side of the Mithraeum a small passage (H. 0.43), leading into the sanctuary.

CIMRM II 457

Read: Istituto poligrafico.