Persia from the Earliest Period to the Arab

144 HISTORY OF PERSIA.
the Parthians in the reign of Vologases III, is so
far worthy of record that it is the first occasion in
which a Roman army had been completely suc-
cessful in its invasion : it is also noteworthy that the
general who accomplished this feat seems to have
acted on his own authority, and without any direct
orders from Rome. The circumstances were these :
a petty war had arisen, owing to the raid of the
Alani into the province of Cappadocia, which had
been, however, crushed for the time by the historian,
Arrian, then its Prefect. But a little later, about the
year A.D. 161, the war became more general, Parthian
troops having crossed the Euphrates, and pushed
on through Syria, into Palestine. To meet these
invaders, the young, pleasure-loving and incompetent
Verus was sent from Rome to take the chief com-
mand, but associated with him were able officers, the
ablest being Avidius Cassius. This officer had at
first a difficult task before him, but, at length, in
A.D. 163, he routed the Parthian king in a great
battle at Europus, and drove him across the Euphrates.
Nor was he slow to follow up his first success.
Having won another considerable battle near Susa,
he besieged, took, and burnt Seleucia on the right
bank of the Tigris, and occupied Ctesiphon
he crossed
on the left. Thence, still advancing,
the Zagros, and, seizing part of Media, enabled
his imperial masters to add to their already assumed
titles of "Armeniacus" and " Parthicus," the new one
of " Medicus."
Parthia was thus for the time completely hum-
bled ; yet had cause for abundant rejoicing in the fate