The Mithraeum.
The temple was discovered during excavations in 1888 within what appeared to be a large house near to the centre of the Roman city. Due to the size of the house and the importance of its location it must have belonged to an important individual and this must certainly be the decurion Marcus Antonius Victorinus who dedicated a number of small altars within the sanctuary. The shrine was orientated north to south and measured 7m wide by 15.03m long. The interior was divided up into three parts- two ante rooms and the sanctuary proper. The front room (Room A: 4.75 x 2.90m)is postulated by the excavators as a Shrine of Mercury. A room (Room B: 0.85x2.90m) was located on the west side and is of uncertain purpose. The middle room (Room C: 5.90x3m) probably served as a narthex. The main part of the shrine was divided into three lateral parts, typical of all mithraea. A central nave about 2.18m wide and 1 meter below ground level was flanked on either side by podium benches for the initiates to recline on during the ceremonies (see Mithraic worship). Steps lead down to the lower floor level of the nave directly from the entrance and the higher benches were accessed by single steps on either side of the bottom nave step. Along the front of the benches, and slightly recessed into them, were placed a pair of small altars (H 0.65 Br. 0.30m) all dedicated by Marcus Antoninus Victorinus.
Read more about this topic: Aquincum Mithraeum (of Victorinus)