The war-history which we have just unfolded did not fail to react with general and lasting effect upon the internal organisation of the Roman political and military system. It has already been pointed out that the corps of the Rhine, holding in the early imperial period the leading position in the army, yielded their primacy already under Trajan to the legions of the Danube. While under Augustus six legions were stationed in the region of the Danube and eight in that of the Rhine, after the Dacian wars of Domitian and Trajan in the second century the Rhine-camps numbered only four, the camps of the Danube ten, and after the Marcomanian war even twelve, legions. Inasmuch as since Hadrian's time the Italian element, apart from the officers, had disappeared from the army, and, taken on the whole, every regiment was recruited in the district in which it was quartered, the most of the soldiers of the Danubian army, and not less the centurions who rose from the ranks, were natives of Pannonia, Dacia, Moesia, Thrace. The new legions formed under Marcus proceeded from Illyricum, and the extraordinary supplemental levies which the troops then needed were probably likewise taken chiefly from the districts in which the armies were stationed. Thus the primacy of the Danubian armies, which the war of the three emperors in the time of Severus established and increased, was at the same time a primacy of Illyrian soldiers; and this reached a very emphatic expression in the reform of the guard under Severus. This primacy did not, properly speaking, affect the higher spheres of government, so long as the position of officer still coincided with that of imperial official, although the equestrian career was accessible to the common soldier through the intervening link of the centurionate at all times, and thus the Illyrians early found their way into that career; as indeed, already, in the year 235, a native Thracian, Gaius Julius Varus Maximinus, in the year 248 a native Pannonian, Trajanus Decius, had in this way attained even to the purple. But when Gallienus, in a distrust certainly but too well justified, excluded the class of senators from serving as officers, what had hitherto held good as to the soldiers became necessarily extended to the officers also. It was thus simply a matter of course that the soldiers belonging to the army of the Danube, and mostly springing from Illyrian districts, played thenceforth the first part also in government, and, so far as the army made the emperors, these were likewise as to the majority Illyrians. Thus Gallienus was followed by Claudius the Dardanian, Aurelianus from Moesia, Probus from Pannonia, Diocletianus from Dalmatia, Maximianus from Pannonia, Constantius from Dardania, Galerius from Serdica; as to the last named, an author writing under the Constantinian dynasty brings into prominence their descent from Illyricum, and adds that they, with little culture but good preliminary training by labour in the field