ulminated in Santa Sophia at Constantinople. Here the centralised plan
was triumphantly adapted to the internal arrangements of the basilica.

Sec. 7. The city of Ravenna, closely connected historically both with Rome
and Constantinople, contains a series of monuments which is of
unequalled interest in the history of the centralised plan. (1) The
mausoleum of the empress Galla Placidia, sister of the emperor Honorius,
who died in 450 A.D., is a building of cruciform shape, consisting of a
square central space covered by a dome, with rectangular projections on
all four sides. The projection through which the building is entered is
longer than the others, and the plan thus forms the Latin cross so
common in the churches of the middle ages. (2) To the same period
belongs the octagonal baptistery, known as San Giovanni in Fonte. (3) In
493 A.D. Theodoric the Ostrogoth obtained possession of Ravenna. To the
period of his rule belongs the Arian baptistery, also octagonal, known
as Santa Maria in Cosmedin. (4) Theodoric died in 526 A.D. His mausoleum
is formed by a polygon of ten equal sides, with a smaller decagonal
upper stage, a circular attic above which bears the great monolithic
dome. In the lower story was the tomb: the internal plan is a Greek
cross, _i.e._ there is a central space with recesses of equal depth on
all four sides. (5) In the year of the death of Theodoric, the octagonal
church of San Vitale was begun. It was consecrated in 547, when Ravenna
had become the capital of the Italian province of Justinian's empire.
Its somewhat complicated plan was clearly derived from an eastern
source, but not from Santa Sophia, which was not begun till 532 A.D. The
central space is almost circular. Between each of the piers which
support the octagonal clerestory at the base of the cupola is an apsidal
recess, with three arches on the ground floor opening into the
encircling aisle, and three upper arches opening into the gallery above
the aisle. On the east side of the central space this arrangement is
broken, and one tall arch opens into the chancel, which ends in a
projecting apse, semi-circular inside, but a half octagon outside. The
aisle with the gallery above thus occupies seven sides of the outer
octagon, the eighth side being occupied by the western part of the
chancel.

[Illustration: Fig. 2. Plan of San Vitale, Ravenna: (1) _narthex_ with
flanking turrets, as originally arranged; (2) central nave; (3) chancel
and