229. A Mithraeum (Reg. I, Is. XVII, 2) built in the foundations of the thermae of
Trajan ("Terme di Mitra").
Becatti, Mitrei Ostia 29ff and fig. 7.
The sanctuary (L. 15.37 Br. 4.55) has been constructed in the northermost part
of a corridor, which was separated from the other underground rooms. Only a
small communication entrance was left open in the 1. wall (Br. 0.80).
The main entrance (Br. 0.75) is on the western side and is accessible by a long
flight of steps which takes its beginning in the upperlying corridor of the therms.
The whole mithraeum is vaulted and has a large arch at a distance of 6.55 mtrs
from the main entrance. This divides the sanctuary in two parts. The vault has in
the sanctuary proper two rectangular funnels. From the fresco-decoration only
some traces of green bushes have been preserved.
Two benches (H. 0.33) along the side-walls; they are accessible by small steps
under the separating-arch; these benches do not run as far as the back-wall but
they leave an open space in which a large base for the cult image. At the ends of
the benches there are two columns (H. 0.55) on which two rough coniform stones
(H. 0.20) were found. Between the ends of the podia in the central aisle there are
two bases, one rectangular (H. 0.50 Br. 0.42) one triangular (H. 0.35 Br. 0.50).