Mitreo di Santo Stefano Rotondo

In 1973-5 a mithraeum was discovered under the church of S. Stephano Rotondo in Rome, in one of the buildings of the Castra Peregrinorum. The monuments are now in the museum of the Baths of Diocletian.

The barrack blocks of the Castra are long and thin and run north-south. Each is divided into two long rooms. Ca. 180AD, the north end of the western room of one of them was turned into a Mithraeum. Some time later, probably in the late 3rd century AD, judging from the monuments, the Mithraeum was widened by absorbing the corresponding part of the eastern room as well.