The Castle Keep was used as a county prison in the late 16th century and until 1633. It is during this late phase of the use of the keep as a gaol that the bodies of those who died or committed suicide in custody (and possibly some who were executed) are likely to have been buried adjacent to the door of the keep.<1> The archaeological evidence shows that they were interred before Wheeley's demolitions (sealed by Wheeley's demolition rubble of 1683) but after the demolition of the chapel, barbican and forebuilding. The main concentration was in the barbican area. All clearly post-date the demolition of forebuilding, chapel and barbican, yet the plan suggests that some were laid out in relation to the sites of those buildings, so that there must have been some trace remaining of them.

They were unaccompanied, except for a small double-ended copper alloy hook, and there was no trace of coffins. Most of the burials were aligned approximately east-west, those in the chapel generally with feet to the east, the remainder usually with feet to the west but at least three were aligned north-south. In one grave, against the south wall of the chapel, there were two skeletons, one on its back, the other face down upon it.

Rudsdale's diary (ERO, D/DU 888/I6, 5. 1. 1933) confirms there were only four graves within the chapel walls; one in the north-east corner contained a female buried on her side, head to the west (Pl. XXXIB), another on its face (Pl. XXXIIA) and three together, one perhaps decapitated, in the south east corner (Pl. XXXIIB).

Drury (1983, pp.406-7) quotes the following entry from Ralph Josselin's diary, for 11 April 1656, which records such a burial: 'heard this morning that James Parnel the father of the Quakers in these parts, having undertaken to fast 40 dayes and nights, was die. 10 in the morning found dead, he was by Jury found guilty of his own death, and buried in the Castle yard'.

Niblett's 1964 excavation at 5 Maidenburgh Street defined two burials (one in situ unfurnished inhumation burial, aligned N to S), c.40-50m to the west of these burials, which might also be related (MCC2091 and MCC2092).

A trial-trenched evaluation in 2014 at Castle House (97 High Street) uncovered an inhumation burial (F5) at the northern end of T3 (most of it lay beyond the trench edge), most likely aligned E to W with the head to the west. Although there was no absolute dating evidence, the report suggests that the inhumation is likely to date to the 16th or 17th centuries when burial of prisoners in the Castle bailey took place.<2>