There is no surviving structure of the 13th century keep: all that stands upon the motte today is a 18th century folly of its earlier existence, however in 1955 an excavation revealed a round structure in pinkish coloured stone similar to that of the original gatehouse of a “somewhat larger” circumference than the modern folly (Hislop et al., 2011, p.5).
The only existing clue as to what the keep looked like is from the 1562 drawing pictured below and a series of archaeological digs, however the exact circumference of the foundation was never revealed. The architecture of the keep has been disputed since publication of Somerville’s Tutbury Castle guide book (1960) which was written shortly after his excavations of the site, where he states that the keep erected upon the motte was “apparently a shell keep” (Somerville, 1960, p.6). The choice of words here could suggest that perhaps he was unsure about the findings, which currently have not been disproved. The only problem with this theory is the size of the motte and the excavations of a stone wall in 1913 and 2006 which is believed to be of the same time as the 15th century rebuild due to similar design and quality. However it is also mentioned that some of the stones bore similar tool marks to the early 14th century gatehouse, suggesting that perhaps they were reused (Hislop et al., 2011, pp.170-71). This causes problems for the ‘shell keep’ theory as if this excavated wall really was of the 15th century then it was most likely the wall that enclosed the round keep of 13th century as shown in the 1562 drawing (figure 2). After studying the plans drawn up from the 1913 excavation the limited space inside of the 15th century wall upon the motte could not have housed a ‘shell keep’ as these were usually quite large and usually built to the rim of the top of the motte as seen in many images of surviving structures (Prestwich & Coulson, 1980, p.46). They usually came about by simply upgrading the palisade wall at the top of the motte to stone walls on which they built structures against on the inside of stone or timber, probably dictated by the foundations (Brown, 1970, p.86).
The drawing shows a large window very similar to the great windows of the gatehouse, a second storey smaller window and what looks to be a small loop probably to illuminate the staircase. There are also two chimney stacks, one medieval in appearance and the other probably a later addition.
It appears to have many similarities with the large windows of other castles of the time such as Pembroke Castle’s keep. This style of window appeared to be very popular in medieval times; they were seen throughout England in castles such as Scarborough and Stokesay Castle.
Pembroke’s round donjon also has holes circling the top which probably supported a wooden structure such as hoardings. However Tutbury’s keep shows extrusions instead of holes. These extrusions could have been stone supports for the wooden beams holding up the hoarding, or just for decoration, however unlikely.
To ensure the best reconstruction can be made, other round donjons of the same time period were studied. Round keeps were really quite rare, especially ones built on mottes due to the foundations not being strong enough.
