ury when Severus,
bishop of Ravenna, miraculously chosen to fill the see, sat in the
council of Sardica in 344 and refused to make any alteration in the
Nicene Creed. About the end of the century Ursus had been bishop and
had built the great cathedral church, the Basilica Ursiana, dedicated
in honour of the Resurrection, with its five naves and fifty-six
columns of marble, its _schola cantorum_ in the midst, and its
mosaics, all of which were finally and utterly destroyed in 1733.
There was too the baptistery which remains and the church of S. Agata
and many others which have perished.

With the church of S. Agata we connect one of the great bishops of the
fifth century, Joannes Angeloptes, who was there served at Mass by an
angel. While with the beautiful little chapel in the bishop's palace,
which still, in some sort at least, remains to us, we connect perhaps
the greatest bishop Ravenna can boast of, S. Peter Chrysologus, for he
built it.

Nor was Placidia herself slow to add to the ecclesiastical splendour
of her city. We have already seen that she built S. Giovanni
Evangelista, rebuilt in the thirteenth century, in fulfilment of her
vow and in memory of her salvation from shipwreck. Close to her palace
she built another church in honour of the Holy Cross, and attached to
it she erected her mausoleum, which remains perhaps the most precious
monument in the city. The church and the monastery which her niece
Singleida built beside it have perished.

But though during the lifetime of Placidia Italy was free from foreign
invasion, the decay of the western empire, of what had been the
western empire, was by no means arrested; on the contrary, Britain,
Gaul, Spain, and Africa were finally lost. Two appalling catastrophes
mark her reign, the Vandal invasion of the province of Africa and the
ever growing cloud of Huns upon the north-eastern frontiers.

[Illustration: THE APSE OF S. GIOVANNI EVANGELISTA]

Placidia's two chief ministers were Boniface and Aetius, either of
whom, according to Procopius, "had the other not been his
contemporary, might truly have been called the last of the Romans."
Their simultaneous appearance, however, finally destroyed all hope of
an immediate resurrection of civilisation in the West. For Boniface,
whose "one great object was the deliverance of Africa from all sorts
of barbarians," betrayed Africa to the Vandals, and to this he was led
by the rivalry and intrigue of Aetius who, on the o