In ILN 2; 9; 16 Oct. 1954. W. F. Grimes gives a survey of the results of the
discovery of a Mithraeum in London at Walbrook near the Mansion house (fig.
ILN 1954, 543 and the reconstruction-drawings on pp 594-595; 534-535).
The temple is lying in the valley of the Walbrook stream and has an overall
length of some 60 ft. and a width of about 25 ft. The temple is well built, its chief
material being Kentish ragstone, with levelling or bonding courses of tile. A feature
of its construction is the massive character of the west end, with a square buttress
on the crest of the apse and massive semicircular buttresses flanking it. There is
some suggestion, yet to be confirmed, that some or all of these buttresses are
afterthoughts added at an early stage while the building was being erected. Their
presence is indicative of the unstable nature of the surrounding ground.
The entrance of the temple was at the east end. Flanking the doorway to the
south is a small annexe, apparently a later addition. Probably a short flight of steps
leads to the floor of the sunken central nave.
The nave, 11 ft. wide, runs the length of the building, from the entrance to the
opening of the apse, the floor of which was raised high above those of the body
of the temple as first designed. The nave is flanked by steeper walls, which not only
carried stone colnmns separating it from the side aisles, but also supported and
revetted the floors of the aisles. Timber had been extensively used in the aisle
floors which served as benches upon which the worshippers reclined. A feature of
the steeper walls is the concrete settings upon which the pillars were erected: there
were seven in all, spaced approximately 6 ft. apart, their diameters varying
between 18 and 20 ins.
The floor of the semicircular apse was raised nearly 3 ft. above the original floor
of the nave. The apse seems to have been given a somewhat elaborate architectural
treatment. That the opening of the apse had some form of division by columns is
suggested both by certain remaining features and by a fragment of a comparatively
slight column, which would appear not to have fitted anywhere else. A series of
four shallow holes against the back wall of the apse is a featnre which gives rise to
some speculation. They may have held the supports for some kind of screen or
reredos, or perhaps had something to do with the lighting arrangements.
A further interesting structure was a timber-lined well in the south-west corner
of the south aisle. It was about 2 ft. deep and a little over 3 ft. square and its
walls were in excellent condition.
This was the temple as it would have appeared in the early years of its existence.
As time went on various structural changes were made, e.g. the steady raising of
the general floor-level. A date after 150 A.D. seems most probable for its erection;
its story goes into the fourth century (coin of Constantine the Great). But by this
time the temple must have become a shadow of its former self: already some part
of its equipment of sacred images had been buried beneath its later floors in
circumstances which are still obscure. Its interior, too, had been drastically
remodelled, and it must have been re-roofed: the floor of the nave was now level
with that of the apse; the stone columns had been removed and had either been
replaced by an arrangement of timbers or had given way to a simple chamber
with no distinction between nave and aisles. Building debris on the last floor shows
that it must have been allowed to fall into disuse at a time when it was still more
or less isolated in its marshy surroundings - a time when already the last years of
the Roman occupation must have been approaching" (Grimes).