This new castle was largely destroyed in 1173 by Henry II, although the huge motte, the second-largest man-made mound in England, remained intact.

[10] Roger Bigod decided to build a new motte and bailey castle, positioning it so as to guard both the town and the local crossing of the Icknield Way over the River Thet and the Little Ouse.

[20] The Bigod family continued to build their grip on the region, taking advantage of their powerful castles at Thetford, Framlingham, Bungay, and Walton.

[21] Roger's son, Hugh Bigod, played a prominent role during the civil war years of the Anarchy, rebelling against King Stephen from his strongholds in East Anglia.

[22] At the end of the war, however, Henry II took the throne and attempted to restore royal power across the region.

Local medieval tradition suggested that the mound had been made by the devil, after he completed the dykes at Narborough and Newmarket, but by the Victorian period academics had concluded that the mound was either of Celtic or Norman origin, with late Victorian scholars correctly concluding that the Norman period was the most likely.

[30] Other traditions claimed that the mound covered a palace filled with treasure, or six silver bells from Thetford Priory.