The entry on Badon is in concurrence with the earlier Historia Brittonum in crediting Arthur with this victory but not with the yet earlier Gildas. The dates are inconsistent as well with Gildas, who wrote when the battle was still in living memory. The legendary tone of the entry can be understood if "shoulders" represents the mistranslation of a Welsh word denoting "shield" and the "cross" could be an emblem or one the numerous alleged pieces of the True Cross. The entry on Camlann seems to be myth, for an Arthur still active around 539 does not fit with other historical clues to the era of his reign despite the strong and tragic tradition the Welsh had on the subject. The Camlann entry may employ a device of fictitious career extension found in the lives of some Welsh saints.
The argument that the entries pertaining to Arthur are historically trustworthy because they are copied from earlier texts is not sustainable. For example, the entry prior to the Badon one records the death of a 350 year old bishop! Regardless, the personages in the Annales are real and Arthur's inclusion points towards his historicity, or at least of the existence of a person whose battles contributed to the creation of the Arthurian myth.
The two entries read :
LXXII Annus. Bellum Badonis, in quo Arthur portavit crucem Domini nostri Jesu Christi tribus diebus et tribus noctibus in humeros suos et Britones victores fuerunt.
Year 72 (c. 519 AD) The Battle of Badon, in which Arthur carried the cross of our Lord Jesus Christ on his shoulders for three days and three nights and the Britons were victors.
XCIII Annus. Gueith Camlann, in qua Arthur et Medraut corruere; et mortalitas in Brittania et in Hibernia fuit.
Year 93 (c. 540 AD) The strife of Camlann in which Arthur and Medraut fell, and there was death in Britain and in Ireland.