Two sub-rectangular pits and an isolated post-hole were identified immediately to the north of the Roman farmstead. The features produced pottery dating to between the mid-4th and mid-7th centuries AD. One of the pits was radiocarbon-dated to AD420-547, whilst fragments of a bone comb and needle from the other pit have a broader typological date range of the 3rd to 13th centuries AD. These features probably represent the remains of Anglo-Saxon sunken-floored buildings.
A large and enigmatic landscape feature that surrounded and enclosed 7ha of relatively high ground in the southern part of the site represented the final significant phase of activity on the site. The roughly D-shaped enclosure was defined by twenty-nine butt-ended and straight-sided ditch segments, with the River Great Ouse and a tributary known as the Rockham ditch forming the eastern and southern sides of the circuit. No artefacts were found in the ditch segments but radiocarbon dates of AD800–980 and 890–1020 from charcoal and animal bone suggest they were dug just after the Viking Great Army had landed in East Anglia (c.AD865).
The Anglo-Saxon Chronicle records a “fortress” at Tempsford built by the Viking Great Army in AD917, as it moved westwards from Huntingdon and East Anglia. In AD1010 it states that Viking forces attacked and captured Tempsford. There is the tantalising possibility that the enclosure represents the Tempsford fortress or battleground referred to in the two separate entries of the Anglo- Saxon Chronicles. The modern village of Tempsford is located just 1km to the south of the site, close to the confluence of the Great Ouse and Ivel rivers.