We may compute, however, that the legion, which was itself a body of six thousand eight hundred and thirty-one Romans, might, with its attendant auxiliaries, amount to about twelve thousand five hundred men.

The peace establishment of Hadrian and his successors was composed of no less than thirty of these formidable brigades; and most probably formed a standing force of three hundred and seventy-five thousand men.
Instead of being confined within the walls of fortified cities, which the Romans considered as the refuge of weakness or pusillanimity, the legions were encamped on the banks of the great rivers, and along the frontiers of the barbarians.

As their stations, for the most part, remained fixed and permanent, we may venture to describe the distribution of the troops.

Three legions were sufficient for Britain.
The principal strength lay upon the Rhine and Danube, and consisted of sixteen legions, in the following proportions: two in the Lower, and three in the Upper Germany; one in Rhaetia, one in Noricum, four in Pannonia, three in Maesia, and two in Dacia.

The defence of the Euphrates was intrusted to eight legions, six of whom were planted in Syria, and the other two in Cappadocia.