[Sidenote: State of the Empire.]

For nearly twenty years after the middle of the third century, the Roman
Empire seemed given over to destruction. It is hard to say whether the
provinces suffered more from the inroads of barbarians who ravaged them
almost at their will, or from the exactions of a mutinous soldiery who
set up an emperor for almost every army; yet both calamities were
surpassed by the horrors of a pestilence which swept away the larger
part of mankind. There was little hope in an effete polytheism, still
less in a corrupt and desponding society. The emperors could not even
make head against their foreign enemies. Decius was killed in battle
with the Goths, Valerian captured by the Persians. But the Teuton was
not yet ready to be the heir of the world. Valerian left behind a school
of generals who were able, even in those evil days, to restore the
Empire to something like its former splendour. Claudius began by
breaking the power of the Goths at Naissus in 269. Aurelian (270-275)
made a firm peace with the Goths, and also recovered the provinces.
Tetricus and Zenobia, the Gaulish Cæsar and the Syrian queen, adorned
the triumph of their conqueror. The next step was for Diocletian
(284-305) to reform the civil power and reduce the army to obedience.
Unfortunately his division of the Empire into more manageable parts led
to a series of civil wars, which lasted till its reunion by Constantine
in 323. His religious policy was a still worse failure. Instead of
seeing in Christianity the one remaining hope of mankind, he set himself
at the end of his reign to stamp it out, and left his successors to
finish the hopeless task. Here again Constantine repaired Diocletian's
error. The edict of Milan in 312 put an end to the great persecution,
and a policy of increasing favour soon removed all danger of Christian
disaffection.