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Ambrosius Aurelianus [called Emrys Wledig]locked

(fl. 5th cent.)
  • David E. Thornton

Ambrosius Aurelianus [called Emrys Wledig] (fl. 5th cent.), military leader, successfully resisted the Anglo-Saxon advance across Britain. What little specific information can be established about him and his activities derives from chapter 25 of the De excidio Britanniae by Gildas, which was the source for Bede's account in his Historia ecclesiastica gentis Anglorum. Gildas describes Ambrosius Aurelianus as (dux'leader' or 'duke') and as a (vir modestus'gentleman'), and states that his parents 'had worn the purple'. The exact implications of this last phrase are difficult to determine with any certainty: it may indicate specifically that the family of Ambrosius had been of Roman senatorial rank, or it may simply mean that he was a member of the late Romano-British nobility. Bede, for instance, assumed Ambrosius's parents were 'of royal birth and title'. However, the modern suggestion that Ambrosius Aurelianus was a kinsman of St Ambrose of Milan, the son of a praetorian prefect called Aurelius Ambrosius, cannot be substantiated beyond the obvious onomastic parallel. Nor is it easy to locate exactly where in Britain Ambrosius was active. Various attempts (some very unconvincing) have been made to identify English place names thought to contain the personal name Ambrosius and which therefore could have been associated with him: for example, Ambresbyrig, the Old English form of Amesbury in Wiltshire, which may mean 'the stronghold of Ambrosius'.

While Gildas does not give any absolute dates for Ambrosius, historians have either followed Bede and dated him c.495, or have argued that Gildas's relative chronology would suggest the 430s or 440s. According to Gildas, the young Ambrosius had survived a period of significant Anglo-Saxon advance, though it had claimed the lives of his parents. He later rallied the Britons and they defeated the enemy in battle, thus marking an improvement in British military fortunes. Subsequently, victory could go either way until the great British victory at 'Mount Badon', though neither Gildas nor Bede connect Ambrosius with this battle, which later tradition associated with the figure of Arthur. It would seem that Ambrosius's own descendants (suboles) sought to maintain his leadership of the Britons (whether just militarily or otherwise is not clear) but, according to Gildas, those of his own day were certainly inferior to their ancestor.

By the early ninth century, the Welsh had developed Ambrosius Aurelianus into a figure of legend, bearing the vernacular name Emrys Wledig (‘Emrys the Overlord’). Thus, there are various notices of him in the Historia Brittonum, where he is synchronized with and generally placed in opposition to Vortigern. The most clearly legendary passage describes how the orphan Emrys identifies a lake under Vortigern's fortress in Snowdonia where a red and a white worm, representing the Welsh and the English respectively, are in constant conflict. From this the boy predicts the ultimate victory of the Welsh and in return is granted all the kingdoms in western Britain by Vortigern. This story may have been composed to explain the origins of the Gildasian Ambrosius Aurelianus, though it does contain elements characteristic of medieval prophetic literature and had later echoes in Geoffrey of Monmouth's Historia regum Britanniae (where the role of Emrys is given to Merlin and the two 'worms' are called dragons) and also in the Welsh medieval vernacular tale Lludd and Llefelys.


  • Gildas: ‘The ruin of Britain’, and other works, ed. and trans. M. Winterbottom (1978)
  • Nennius, ‘British history’ and ‘The Welsh annals’, ed. and trans. J. Morris (1980)
  • The Historia regum Britannie of Geoffrey of Monmouth, ed. N. Wright, 1: Bern, Bürgerbibliothek, MS 568 (1985)
  • The Mabinogion, trans. G. Jones and T. Jones, revision of 1974 edn (1984)
  • D. N. Dumville, Histories and pseudo-histories of the insular middle ages (1990)
  • J. N. L. Myres, The English settlements (1986)
Bede, ed. and trans. B. Colgrave & R. A. B. Mynors, OMT (1969); repr. (1991)
Monumenta Germaniae Historica, Auctores antiquissimi