No original Anglo-Saxon charter bearing an AD date earlier than 736 is extant, which seems to suit the traditional view that dating by the Era of the Incarnation, as opposed to the indiction or regnal years, was due to its popularisation by Bede's treatise De temponim ratione and his Historia ecclesiastica. ‘Consequently,’ in R. L. Poole's words, ‘not a few Anglo-Saxon charters which contain the date from the Incarnation have been condemned as spurious or corrupt.’ He then added that ‘there seems, however, to be no reason to suppose that the adoption of this era was originated by the treatise of Bede’, maintaining that it is ‘much more likely’ that it was derived from the Easter Tables of Dionysius Exiguus, arguing on the basis of the accounts of St Wilfrid's instruction at Rome and his speech at the Synod of Whitby in 664, that the saint championed the use of the Dionysian computation. Kenneth Harrison has shown how likely this is on various grounds. These include a defence of four charters bearing AD dates in the seventh century and arguably connected with Wilfrid. Harrison's case has been accepted by Nicholas Brooks, though not by Anton Scharer, and Harrison later brought two more charters into the discussion. The earliest of Harrison's charters, the foundation charter of Bath, dated AD 676 and attested by Wilfrid, and a charter concerning Ripple, Worcestershire, dated AD 680, will be discussed in detail below. Three others, all attested by Wilfrid, belong to the group of charters which Anton Scharer and Patrick Wormald associate with Eorcenwald, bishop of London, who also attests: Casdwalla of Wessex's grant of Farnham, Surrey, dated (problematically)AD 688, Eorcenwald's grant of Battersea, Surrey, dated AD 693, and his charter for Barking monastery, in which his visit to Rome is dated (again problematically) to AD 677. It is entirely possible that Wilfrid was responsible for the inclusion of the annus Domini in these charters, even if their actual drafting was done by Eorcenwald or one of his circle; the absence of the annus Domini from the other credible ‘Eorcenwald’ charters is significant. (Eorcenwald attests the Bath foundation charter, but so does Wilfrid.) Harrison's remaining charter is Æthelred of Mercia's confirmation of a grant in Thanet to the Kentish abbess Æbbe, dated AD 691 in the best manuscript.6 Significantly, this is the only one of the thirteen charters between 675 and 737 in Elmham's Historia Monasterii S. Augustini Cantuariensis to bear an AD date. Wilfrid does not attest — the confirmation carries no witness list — but Brooks comments that, of the four charters originally discussed by Harrison (Birch, Cartularium Saxonicum, nos 42, 43, 51 and 72), only BCS 42 [the Thanet charter] has no evident connection with Wilfrid. Yet it shows Wilfrid's friend and protector, King Æthelred of Mercia, intervening in Kent by force in January 6gi (‘dum ille infirmaverat terram nostram’) at a time when the see of Canterbury was vacant. Wilfrid was by this time again running into difficulties with the Northumbrian king, and his biographer claims that he had been offered the succession to the see of Canterbury by Archbishop Theodore himself.