The explanation as to when (and why) this corner of Devon became associated with Hubba and arx Cynuit predates Tristram Risdon. But Risdon’s own contribution is (a bit) clearer.
He seems to have been the first to name the village of Appledore as the place where the Danish fleet landed in 878. The text below is from the earliest edition (1714) of his Survey which, though generally unsatisfactory, differs little from the equivalent paragraph in the more reliable 1811 edition:
APLEDORE is in the Saxon Tongue APULTREO, [ … ] it is the Outlet of two notable Rivers into the Sea, and the next Harbour for Ships within the Bar. In this Place it was that Hubba, the Dane, in the Days of King Alfred that Saxon monarch, landed with 33 Sail of Ships, coming out of South Wales, where he had wasted all in his Way with Fire and Sword. And hereabout it was he laid Siege to the Castle of Kenwith; which Place some have sought for, as it were for Ants Paths, but found it not, unless they guess Hennaborough, a Fort not far hence …
His source would seem to be, in part, Asser (for the mention of the slaughter in South Wales). But ‘Appledore, in the Saxon’s tongue Apultreo’ is puzzling. Appledore isn’t mentioned at all in the Post-Conquest Domesday Book, and its first recorded name, 1335, is given as le Apildore in the manor of Northam. Neither Asser nor the Anglo-Saxon Chronicle, the two sources dating from Saxon times, mentions where the raid took place, so what was Risdon’s source for saying that Appledore had been called ‘Apultreo’ in Saxon times? Where was this recorded?
In fact, there is evidence of it as a name for Appledore in John of Worcester’s 12th-century Chronicon ex chronicis. He records the arrival of a Danish fleet at the river mouth and how they constructed a fortress ‘in loco qui dicitur Apultreo’. Was Risdon’s source John of Worcester? It’s possible, though John, following the Anglo-Saxon Chronicle, was recording a Danish landing in 892 at Appledore in Kent, not Appledore in Devon. Lord William Howard published his edition of John’s chronicle – attributed then to Florence of Worcester – in 1592, though the name appears there as ‘Apultrea’ rather than ‘Apultreo’, so is less likely to be the source.
The antiquarian William Lambarde, of the circle of Archbishop Matthew Parker and a scholar of Anglo-Saxon, describes this same event in his Perambulation of Kent (1576). Lambarde writes: ‘Apledore, corruptly, for the Saxon Apultreo: in Latine Malus, that is, An Apletree’. This seems a more likely source for Risdon’s own ‘Appledore, in the Saxon’s tongue Apultreo’.
The Anglo-Saxon Chronicle itself records the 892 raid on Appledore: a large fleet of 250 ships sailed from Boulogne into the mouth of the Lympne, followed soon after by a smaller fleet – 80 ships led by the Danish chief Hæsten – which entered the mouth of the Thames.
þa comon up on Limene muþan. mid .ccl. (hunde) scipa. Se muþa is on easte weardre Cent … Þa sona æfter þæm com Hæsten mid .lxxx. scipa up on Temese muðan, 7 worhte him geweorc æt Middeltune, 7 se oþer here æt Apuldre [ … ] Wæs Hæsten þa þær cumen mid his herge, þe ær æt Middeltune sæt. 7 eac se micla here wæs þa þærto cumen, þe ær on Limene muþan sæt æt Apuldre .
The larger fleet landed at Appledore, which was a port at that time; but the Saxon name given here is not Apultreo but Apuldre (in all the extant manuscripts, or Apuldran in the Latin Annals of St Neots). Apultreo looks like apul + treów and Bosworth-Toller’s Anglo-Saxon Dictionary records the forms æpel-tre, æppel-treów, along with æppelder, æppeldor, apulder, apuldor, apuldur, all in the sense of apple-tree.
However, these are not Apultreo, the exact form common to John of Worcester, William Lambarde – and Risdon. Since the first two refer to Appledore in Kent, it looks as if Risdon made an assumption: that since the place-name Appledore in Kent derived from the Saxon Apultreo, Appledore in Devon must have the same origin. Perhaps the raid on the Kentish Appledore at the mouth of the river Lympne/Limene caused him to realise that the mouth of the river Taw was a likely place for the raid of 878 …
However, one other fact suggests that Risdon was not the onlie begetter of this Devon legend. To whom was he referring when he wrote: ‘And hereabout it was he laid Siege to the Castle of Kenwith; which Place some have sought for, as it were for Ants Paths, but found it not, unless they guess Hennaborough, a Fort not far hence …’? Who had already been speculating that Hennaborough, or Henny Castle, was this ‘Castle of Kenwith’? Or was Risdon inventing them to add support to his own theory?