North of the Thames indications are even vaguer. Professor Oman is of opinion that all the Romano-British cities in Eastern Britain perished very early, mainly on the authority of Gildas, who appears to give ‘a picture of a Celtic Britain which does not extend anywhere towards the east coast.’ To attempt to make any definite geographical deductions from a writer so vague as Gildas is rash; as a fact, we know that his five dynasts are only some of several, and the territory of one of them who bears the most suggestive name of all is not specified. Aurelius Caninus may just as well have been king of London and Verulam as of Glevum, Corinium, and Aquæ Sulis. Opinion is steadily trending in the direction of a belief in the continuous existence of London through the ‘lost’ centuries. This is too great a question to discuss here, but on practical military grounds it may be pointed out that London, strongly fortified, apparently populous, and situated astride of a great river, was eminently fitted to be the curb of a barbarian invasion. There is also to be considered the curious fact that the country round London was called Middlesex, as if it at one time formed a sort of buffer between East and West Saxons. The name certainly seems to show that London and its territory became English late. The English north of the Thames possibly lay north and east of a line drawn from Leicester to the mouth of the Thames. If so, their abode corresponded roughly to the later ‘Danelaw.’ They probably formed, like the Vikings, a confused mingling of petty kingdoms, earldoms, and the camps of war bands. What was going on north of the Humber is not known, but certainly the Bernician Angles in Lothian were fighting hard with the British kingdoms of Strathclyde and Reged. Not until 547 did they take Bamborough. The beginnings of Deira were probably still later; it is not at all certain that the English had as yet any footing in Yorkshire. Had a second Ambrosius Aurelianus or Artorius arisen to coerce the warring British states into unity, the English settlements might have been conquered, as were those of the Danes by Alfred and Eadward I. This was not to be. About 540 the Anglian settlements were fast increasing in strength. The whole ‘Angel-cynn,’ in fact, were streaming over to Britain every year as fast as their ships could take them. Probably they were forced on by the disorder in Europe, and the pressure caused by the migrating Slavs and the raiding Avars with their kindred tribes. At any rate, about 550 we find the English once more on the move, and this time the Britons had no Ambrosius or Arthur to save them.