cluded by the year A.D. 283, when he
found himself suddenly engaged in hostilities on the opposite side of
the empire.

[Illustration: PLATE 17]

Rome, in the latter part of the third century, had experienced one of
those reactions which mark her later history, and which alone enabled
her to complete her predestined term of twelve centuries. Between the
years A.D. 274 and 282, under Aurelian, Tacitus, Probus, and Carus, she
showed herself once more very decidedly the first military power in
the world, drove back the barbarians on all sides, and even ventured to
indulge in an aggressive policy. Aurelian, as we have seen, was on the
point of invading Persia when a domestic conspiracy brought his reign
and life to an end. Tacitus, his successor, scarcely obtained such a
firm hold upon the throne as to feel that he could with any prudence
provoke a war. But Probus, the next emperor, revived the project of a
Persian expedition, and would probably have led the Roman armies into
Mesopotamia, had not his career been cut short by the revolt of the
legions in Illyria (A.D. 282). Carus, who had been his praetorian
prefect, and who became emperor at his death, adhered steadily to his
policy. It was the first act of his reign to march the forces of the
empire to the extreme east, and to commence in earnest the war which had
so long been threatened. Led by the Emperor in person, the legions once
more crossed the Euphrates.

Mesopotamia was rapidly overrun, since the Persians (we are told) were
at variance among themselves, and a civil war was raging. The bulk of
their forces, moreover, were engaged on the opposite side of the empire
in a struggle with the Indians, probably those of Afghanistan. Under
these circumstances, no effectual resistance was possible; and, if
we may believe the Roman writers, not only was the Roman province of
Mesopotamia recovered, but the entire tract between the rivers as far
south as the latitude of Bagdad was ravaged, and even the two great
cities of Seleucia and Ctesiphon were taken without the slightest
difficulty. Persia Proper seemed to lie open to the invader, and Carus
was preparing to penetrate still further to the east, when again an
opportune death checked the progress of the Roman arms, and perhaps
saved the Persian monarchy from destruction. Carus had announced his
intention of continuing his march; some discontent had shown itself;
and an oracle had been quoted which declared that a Rom