he centuriate had disappeared for lack of volunteers of this
class and with its disappearance began a decline in discipline and
training. The construction of the fortified camp was no longer required,
the soldier's heavy pack was discarded, and before the close of the fourth
century the burdensome defensive armor was also given up. In equipment and
tactics the Roman troops of the late empire were on a level with their
barbarian opponents. Just as the Roman empire was unable to assimilate the
barbarian settlers within its frontiers, so the Roman army proved unable
to absorb the barbarian elements within its ranks.

*Foederati.* The decline in efficiency of the Roman troops and the
confessed inability of the state to deal with its military obligations led
to the taking into the Roman pay of warlike peoples along the Roman
frontiers. Such peoples were called federated allies (_foederati_), and
guaranteed to protect the territory of the empire in return for a
stipulated remuneration in money or supplies. Such were the terms upon
which the Goths were granted lands south of the Danube by Theodosius the
Great. But in this case, as in others, it is hard to distinguish between
subsidies paid to _foederati_ and the payments made by many emperors to
purchase immunity from invasion by dangerous neighbors. A danger inherent
in the system was that the _foederati_ might at any moment turn their arms
against their employers. Retaining as they did their political autonomy
and serving under their own chiefs, the _foederati_ were not regarded as
forming a part of the imperial forces.

*The duces and the magistri militum.* We have already referred to the
complete separation of military and civil authority. This was carried out
as far as the border troops were concerned by Diocletian. He divided the
frontiers into military districts which corresponded to the provinces and
placed the garrisons in each under an officer with the title of _dux_. The
_duces_ of highest rank were regularly known as _comites_ (counts). Under
Diocletian the praetorian prefects remained the highest military officers,
and were in command of the field army. As we have seen, Constantine I
deprived the praetorian prefecture of its military functions and appointed
two new commanders-in-chief--the master of the foot (_magister peditum_)
and the master of the horse (_magister equitum_). Under the successors of
Constantine these offices were increased in number and the disti