Geoffrey Greatrex (2005). Byzantium and the East in - Kaveh Farrokh

The Cambridge Companion to the Age of Justinian
Because of Maurice’s aid, they obtained very favourable terms, extending
the frontiers of the empire deep into what had been Persarmenia.
But Maurice’s intervention provided Khusro with an excellent pretext
for Khusro II to follow his example in the wake of Maurice’s overthrow
and the accession of Phocas in 602. Persian armies proceeded to overrun
almost the entire eastern empire, seizing Syria, Egypt, Armenia, and
Palestine; one Persian force even reached Constantinople in 626. Only
with the greatest difficulty was the emperor Heraclius (610–641) able to
turn the tide against the invaders and to undermine Khusro’s position
by laying waste the heartlands of the Persian Empire. The two sides then
came to terms, but it was too late: both powers had exhausted themselves
through decades of warfare. Consequently they were unable to
defeat the Arab armies that came forth to wrest their territories from
them in the 630s. As Peter the Patrician had predicted, by squandering
their resources, the two sides were “conquered by those who ought
not to defeat them.” 37
Justinian and the Frontier Peoples
between Rome and Persia
A glance at some maps illustrating the extent of the Roman and Persian
empires might give the impression of a neat frontier line dividing the
two powers, stretching from the Caucasus mountains in the north to
the Syrian desert in the south (Maps 14 and 15). The reality, however,
was far more complex, as one might expect if one considers the nature
of the terrain in question: neither the mountainous districts of Armenia
and the Caucasian kingdoms nor the Syrian steppes have ever been easy
for an external power to control. As we shall see, both the Romans and
the Persians struggled to impose their authority on these frontier zones;
sometimes they employed negotiation, at other times they resorted to
coercion. In some cases it is difficult even to determine the precise status
of a region or people – whether it was actually in the Roman Empire
or outside it. For example, to the north of Roman Mesopotamia lay a
region that, until the late fifth century, was governed by five Armenian
satraps, even though it was considered to be part of the empire. Beyond
it to the north lay Armenia Interior, a Roman province from the late
fourth century onwards, which was integrated only gradually into the
structure of the empire. 38 As will become clear, during the sixth century
a concerted attempt was made to consolidate the Roman grip on the
frontier territories.
490
Cambridge Companions Online © Cambridge University Press, 2006