The further steps taken by his co-Cæsar Constantius to put an end to the revolt of Carausius are very instructive. He first recovered the haven of Gesoriacum (Boulogne), and cut off the connexion of the British fleet with Gaul. Then he turned northward again upon the districts from whence the Frankish and Saxon pirates had been accustomed to make their ravages upon Britain and Gaul. They were, as has been said, in league with the British usurper, but succumbed to the arms of Constantius. The first use he made of his victory over them was to repeat the policy of his predecessors--to deport a great multitude into those very Belgic districts which they had depopulated by their ravages. This was the time when the districts around Amiens and Beauvais, once inhabited by the Bellovaci, and further south around Troyes and Langres, where the Tricassi and Lingones had dwelt, were colonised by Franks, [p285] Chamavi, and Frisians; and Eumenius,[411] in his Panegyric, represented them, as Probus had described the Alamanni, as now tilling the fields they had once plundered, and supplying recruits to the Roman legions. A '_pagus Chamavorum_' existed in the ninth century in this district, and so bore witness to the extent and permanence of this colony of _Chamavi_.[412] Similar evidence for the other districts, as we shall have occasion to see hereafter, is possibly to be found in the names of places with a Teutonic termination remaining to this day, though the language spoken is French. A recent German writer, in a sketch of the reign of Diocletian, makes the pregnant remark that when account is taken of all the masses of Germans thus brought into the Roman provinces, partly as colonists and partly as soldiers, it becomes clear that the northern districts of Gaul were already half German before the Frankish invasion. These German settlers were valuable at the time as tillers of the land, payers of tribute, and as furnishing recruits to the legions; but in history they were more than this, for they were, partly against their will, the pioneers of the German '_Völkerwanderung_.'[413] «Alamanni in Britain.» We have seen that Probus had deported Alamanni into Britain in pursuance of this continuous [p286] policy. It is curious to observe that when Constantius soon after (in A.D. 306) died at York, and Constantine was proclaimed Emperor in Britain, one of his supporters was Crocus or Erocus,[414] a king of the Alamanni, proving that there were Alamannic soldiers in Britain under their own king--probably, more properly speaking, a sept or clan under its own chief--at that date.