Before leaving the neighbourhood it now only remains to try and determine who the brave men were who were buried at Avebury, and who the victors who raised the mound at Silbury, assuming that the one is a burying place, and the other a trophy. Some years ago I suggested it was those who fell in Arthur's last and greatest battle of Badon Hill, fought somewhere in this neighbourhood in the year A.D. 520,[103] and nothing that has since occurred has at all shaken my conviction in the correctness of this determination,[104] but a good deal has tended to confirm it. The authors of the 'Monumenta Britannica' fix the site of this battle at Banesdown, near Bath, which is the generally received opinion.[105] Carte, and others, have suggested Baydon Hill, about thirteen miles west by north from Avebury, while Dr. Guest carries it off to Badbury, in Dorset,[106] a distance of forty miles. Unfortunately, Gildas, who is our principal authority on this matter, only gives us in three words all he has to say of the locality in which it was fought--"Prope Sabrinum Ostium";[107] and it has been asserted that these words are an interpolation, because they are not found in all the ancient MSS. If they are, however, an insertion, they are still of very ancient date, and would not have been admitted and repeated if they had not been added by some one who knew or had authority for introducing them. As the words are generally translated, they are taken to mean near the mouth of the Severn, a construction at once fatal to the pretensions of Bath, which it is impossible any one should describe as near that river, even if any one could say where the mouth of that river is. It is most difficult to determine where the river ends and the estuary begins, and to a mediæval geographer, especially, that point must have been much nearer Gloucester than even Bristol. This, however, is of little consequence, as the words in the text are not "Sabrinæ ostium," but "Sabrinum ostium"; and as the river is always spoken of as feminine, it is not referred to here, and the expression can only be translated as "near the Welsh gate." Nor does it seem difficult to determine where the Welsh gate must have been.