He tells how a British king (to whom later tradition assigns the name
Vortigern) invited in the Anglo-Saxons as allies against the troublesome
northern Scots and Picts, and how the Anglo-Saxons, victorious against
these tribes, soon turned in furious conquest against the Britons
themselves, until, under a certain Ambrosius Aurelianus, a man 'of Roman
race,' the Britons successfully defended themselves and at last in the
battle of Mount Badon checked the Saxon advance.

Next in order after Gildas, but not until about the year 800, appears a
strangely jumbled document, last edited by a certain Nennius, and entitled
'Historia Britonum' (The History of the Britons), which adds to Gildas'
outline traditions, natural and supernatural, which had meanwhile been
growing up among the Britons (Welsh). It supplies the names of the earliest
Saxon leaders, Hengist and Horsa (who also figure in the 'Anglo-Saxon
Chronicle'), and narrates at length their treacherous dealings with
Vortigern. Among other stories we find that of Vortigern's tower, where
Gildas' Ambrosius appears as a boy of supernatural nature, destined to
develop in the romances into the great magician Merlin. In Nennius' book
occurs also the earliest mention of Arthur, who, in a comparatively sober
passage, is said, some time after the days of Vortigern, to have 'fought
against the Saxons, together with the kings of the Britons, but he himself
was leader in the battles.' A list, also, is given of his twelve victories,
ending with Mount Badon. It is impossible to decide whether there is really
any truth in this account of Nennius, or whether it springs wholly from the
imagination of the Britons, attempting to solace themselves for their
national overthrow; but it allows us to believe if we choose that sometime
in the early sixth century there was a British leader of the name of
Arthur, who by military genius rose to high command and for a while beat
back the Saxon hordes. At most, however, it should be clearly realized,
Arthur was probably only a local leader in some limited region, and, far