Perennis, Praefect of the Praetorian Guards, who had been sent from Rome (A.D. 185) to carry out the reform.[269] E. 2.--This episode shows us how great a solidarity the Army of Britain had by this time developed. It was always the policy of Imperial Rome to recruit the forces stationed throughout the Provinces not from the natives around them, but from those of distant regions. Inscriptions tell that the British Legions were chiefly composed of Spaniards, Aquitanians, Gauls, Frisians, Dalmatians, and Dacians; while from the 'Notitia' we know that, in the 5th century, such distant countries as Mauretania, Libya, and even Assyria,[270] furnished contingents. Britons, in turn, served in Gaul, Spain, Illyria, Egypt, and Armenia, as well as in Rome itself. E. 3.--The outburst which led to the slaughter of Perennis was but the dawn of a long era of military turbulence in Britain. First came the suppression of the revolt A.D. 187 by the new Legate,[271] Pertinax, who, at the peril of his life, refused the purple offered him by the mutineers,[272] and drafted fifteen hundred of the ringleaders into the Italian service of Commodus;[273] then Commodus died (A.D. 192), and Pertinax became one of the various pretenders to the Imperial throne; then followed his murder by Julianus, while Albinus succeeded to his pretensions as well as to his British government; then that of Julianus by Severus; then the desperate struggle between Albinus and Severus for the Empire; the crushing defeat (A.D. 197) of the British Army at Lyons, the death of Albinus,[274] and the final recognition of Severus[275] as the acknowledged ruler of the whole Roman world. E. 4.--Of all the Roman Emperors Severus is the most closely connected with Britain. The long-continued political and military confusion amongst the conquerors had naturally excited the independent tribes of the north. In A.D. 201 the Caledonians beyond Agricola's rampart threatened it so seriously that Vinius Lupus, the Praetor, was fain to buy off their attack; and, a few years later, they actually joined hands with the nominally subject Meatae within the Pale, who thereupon broke out into open rebellion, and, along with them, poured down upon the civilized districts to the south. So extreme was the danger that the Prefect of Britain sent urgent dispatches to Rome, invoking the Emperor's own presence with the whole force of the Empire.