is 39 ft. broad, and the aisles 26 ft. The transept is
about 136 ft. long, with an apse 32 ft. 6 in. broad opening from it, 21
ft. deep. The exterior length of the building is 218 ft. The round
arches from the aisles to the transepts are older than the nave arcade.
The columns are antique; that on the south has also a Corinthian cap,
but the base is Romanesque. The base of the northern column is a
shapeless block; the cap is like those of the nave, but the super-abacus
is plain. Across the transepts two round arches are thrown in a line
with the aisle walls, resting on very thin columns of cipollino; that on
the south is of several pieces not belonging to each other. The caps
vary in design. North and south of these arches are the chapels, with
their apses. The arch of the apse is round, with two antique granite
columns; it had three small round windows in it. The bishop's throne is
from the earlier church. Beneath the late-Gothic seats round the apse
are the seats of Poppo's time, with remains of inscriptions: the
pavement of marble slabs and mosaic patterns is also due to him.

In 1896 frescoes of the eleventh century were discovered beneath the
rococo plaster-work in the semi-dome. In the centre is the Madonna and
Child enthroned in a vesica above six saints, and surrounded by the
symbols of the Evangelists. The saints to the spectator's right are SS.
Hermagoras, Fortunatus, and Euphemia; to the left are SS. Mark, Hilarus,
and Titianus. Among them are persons on a smaller scale--Poppo holding
his church, the emperor (Conrad II.) and the empress, an unnamed person,
and a boy "Einricus" (afterwards Henry III.); a border of medallions,
with heads and peacocks alternately, surrounds the field. Below, between
the three windows, are six more saints, three on each side. Two
different hands can be traced. In the crypt are also paintings of the
eleventh and twelfth centuries, the difference in technique being
marked. On the vaults are the legends of SS. Hermagoras and Fortunatus;
in the lunettes the life of the Virgin, angels, Apostles, and saints,
and on the soffits of the arches; and painted hangings in outline with
figure-subjects upon them, on the lower part of the wall. There is one
subject from the life of S. Mark. Two kinds of intonaco are used, one
hard and white, the other grey and sandier. There are two rows of
pillars in the crypt, six in the wall round the apse, and two
(Renaissance) at the sides of the westward ni