Thunder of the Gods (56 page)

As for horsemen, the importance of the empire’s 75,000 or so
auxiliary cavalrymen
, capable of much faster deployment and manoeuvre than the infantry, and essential for successful scouting, fast communications and the denial of reconnaissance information to the enemy, cannot be overstated. Rome simply did not produce anything like the strength in mounted troops needed to avoid being at a serious disadvantage against those nations which by their nature were cavalry-rich. As a result, as each such nation was conquered their mounted forces were swiftly incorporated into the army until, by the early first century BC, the decision was made to disband what native Roman cavalry as there was altogether, in favour of the auxiliary cavalry wings.

Named for their usual place on the battlefield, on the flanks or ‘wings’ of the line of battle, the cavalry cohorts were commanded by men of the equestrian class with prior experience as legion military tribunes, and were organised around the basic 32-man
turma
, or squadron. Each squadron was commanded by a
decurion
, a position analogous with that of the infantry centurion. This officer was assisted by a pair of junior officers: the
duplicarius
or
double-pay
, equivalent to the role of optio, and the
sesquipilarius
or
pay-and-a-half
, equal in stature to the infantry watch officer. As befitted the cavalry’s more important military role, each of these ranks was paid about 40 per cent more than the infantry equivalent.

Taken together, the legions and their auxiliary support presented a standing army of over 400,000 men by the time of the events described in the
Empire
series. Whilst this was sufficient to both hold down and defend the empire’s 6.5 million square kilometres for a long period of history, the strains of defending a 5,000-kilometre-long frontier, beset on all sides by hostile tribes, were also beginning to manifest themselves. The prompt move to raise three new legions undertaken by the new emperor Septimius Severus in AD 197, in readiness for over a decade spent shoring up the empire’s crumbling borders, provides clear evidence that there were never enough legions and cohorts for such a monumental task. This is the backdrop for the
Empire
series, which will run from AD 192 well into the early third century, following both the empire’s and Marcus Valerius Aquila’s travails throughout this fascinatingly brutal period of history.