Badbury is a strong candidate for the location of Arthur’s battle of Baddon. It is an Iron Age hillfort located at the intersection of Roman roads. The entries for Cerdic and Cynric in the AC suggest it would have been an area fought over by the emerging kingdom of Wessex. It is close to the Roman military base at Hod Hill which is next to the River Stour and used the port at Hengistbury Head.
An archaeological excavation took place at Badbury in 2004. Besides the expected material from the Iron Age, the finds included a late Roman bronze spiral ring on a chalk floor which had charcoal, all three samples of which were dated to the period 480 to 520.
That the ASC makes no mention of Baddon is not surprising as the policy was clearly not to mention their defeats. A further example of this are the battles mentioned in the AC and also referred to in the ByT, dated to the year 721:
And the battle of Heilin, with Rhodri Molwynog, took place in Cornwall; and the action of Garthmaelog, and the fight of Pencoed in South Wales. And in those three battles the Britons were victorious.
Moreover, although the ASC is reasonably accurate, it is clear that in the Arthurian age the information has been manipulated. The entries for the years 495 and 508 look similar to those of 514 and 527 respectively, seperated by 19 years, the Metonic cycle. It would appear that, by the use of repetition, the chronicle blanked out a disastrous period for the Saxons.
 Williams, J., 1860, 5
The AC A-text indicates the battle of Baddon occurred 63 years after Pope Leo’s dating of Easter which occurred in the year 455. This points to a date for Baddon of 518.
The AC B-text describes the occurrence of an eclipse thus:
Anus dies tenebrosa sicut nox.
This is likely to be that which occurred on 23 December 447 and would have been visible over Britain. The document shows Baddon as occurring 71 years later. This too indicates Baddon took place in the year 518.
Further confirmation of this date is given by the ASC and DE as can be seen in the post entitled The Adventus Saxonum.