The Britons, according to Gildas, were for a while unable to make any effective resistance to the attacks of their enemies, who were being steadily reinforced from oversea; but after a weary time of ravage and defeat, a Roman (Romanized Briton) named Ambrosius Aurelianus, perhaps a son of the Ambrosius who had opposed Vortigern, took the lead. The plan of accepting the suzerainty of Kymric dynasts for the sake of peace and unity had led to disaster, and men were ready to rally to one who stood for Roman traditions. Ambrosius succeeded in organizing an effective resistance, and the result seems to have been that he was acknowledged as king in the south at least. The ‘Historia Brittonum’ states that Vortigern’s son Pascentius was subject to him, and in the Welsh traditions he appears as ‘Emrys Gwledig.’ Nevertheless, the success was only partial. It appears certain that the Teutons were firmly established on the eastern coast as well as in Kent and Sussex. Ambrosius fought against them incessantly with varying fortune all through his reign, but if he confined them to the territory which they had already won, and checked their raids inland, it was as much as he could do. The invaders’ base was the sea, and they could attack when and where they pleased; we do not hear, nor is it probable, that Ambrosius succeeded in organizing a navy, and no other means could have definitely checked the advance. On the other hand, Ambrosius probably had to some extent the advantage which unity of command gives, while his opponents’ operations would often be disunited and erratic. In the midst of the struggle Ambrosius died. His gallant efforts appear to have produced important results. Not only was he able to pass on his power to his descendants, as Gildas witnesses, but a more or less united resistance was kept up against the invaders. In the place of Ambrosius the cities and kings appear to have chosen as Commander-in-chief, or _Dux Bellorum_, a certain Artorius, famed in legend as ‘King Arthur.’ He may or may not have been the immediate successor of Aurelianus; perhaps here again Geoffrey of Monmouth had some authority for interposing a third figure between the two, though ‘Uther’ looks suspiciously like a variation of Arthur. Artorius may have been a relation of Ambrosius. At any rate, his leadership was signalized by a long succession of victories. The ‘Historia Brittonum’ gives the rather suspicious round number of twelve, but as it is obtained by there having been four battles in the same locality, there is no obvious reason for doubting it.