The Roman Army, 31 BC–AD 337: A Sourcebook

The army in the field 91
reputation is greater than their achievements, since, although they have
never taken anything from the Romans and have moreover surrendered
certain parts of their own territory, they have never been completely
conquered, but even now are a match for us in their wars against us
when they become involved in them… (There follows a description of
the Parthian army and the climatic conditions). For this reason they do
not campaign anywhere during this season (winter, when the damp
weather affected their bowstrings). For the rest of the year, however,
they are very difficult to fight against in their own land and in any area
that resembles it. For they can endure the blazing heat of the sun because
of their long experience of it, and they have found many remedies for
the shortage of water and the difficulty of finding it, with the result
that they can easily drive away anyone who invades their land. Outside
this land, beyond the Euphrates, they have now and again won some
success in battles and sudden raids, but they cannot wage a continuous,
long-term war with any people, both because they face completely
different conditions of climate and terrain, and because they do not
prepare a supply of provisions or money.
This is about the only detailed, rational analysis we have of a power on the
periphery of the Roman empire that might be perceived as a threat. Dio is
probably expressing a late-second century view based on the accumulated
wisdom of Roman experiences in the east. Note also his comments (80. 3) on
the rise of the Persians, who around AD 224 replaced the Parthians as the
dominant force east of the Euphrates.
152 Josephus (1st C.AD), Jewish War 3. 115–26
But Vespasian, eager to invade Galilee himself, marched out from
Ptolemais after drawing up his army in the usual Roman marching
order. (Section 116) He ordered the auxiliary lightly-armed troops and
the archers to go on ahead to cut off any sudden attacks by the enemy
and to investigate woodland which was suspicious because of its
suitability for ambushes. Next followed a detachment of heavily-armed
Roman soldiers, both infantry and cavalry. (Section 117) After them
marched ten men from each century carrying their own equipment and
the implements for measuring out the camp. (Section 118) Next came
the engineers whose task was to straighten bends in the road, level
rough areas, and cut down woodland which was blocking the way, so
that the army should not be exhausted by a difficult march. (Section
119) Behind these men Vespasian placed his personal equipment and
that of his subordinate commanders and a strong cavalry guard to
protect it. (Section 120) He himself rode behind these with infantry