Description from record TR 15 NE 193 :
Prior's Chapel, Grade I, c1260. Only the open undercroft remains incorporated in the brick library. (The Hawley Harrison Library) of 1660. (1) [TR 15145795] Prior's Chapel [NR] (Site of) [NAT]. (2)

The Canterbury UAD states that records inform us that Prior Roger de St. Alphege, from 1258 to 1263, completed a chapel between the Dormitory and the Infirmary, which appears to have been dedicated to the Virgin Mary. The style of the substructure, however, shows that it was begun by his predecessor Prior Nicholas of Sandwich. This, which is known as the Prior's Chapel, being intended for the private use of the Prior, is placed on the south side of the Infirmary Cloister, between the Lavatory Tower and Infirmary. Its floor was on the level of the upper gallery, and was sustained by an open, vaulted ambulatory below. This replaced the portion of the original south alley which occupied that position. Thus the covered access from the Great Cloister to the Infirmary was still preserved. The Chapel's wall carried strong buttresses to the north and south with an unglazed window between each, as in the cloisters of this period. After the Reformation, about c. 1700 the Chapel was pulled down and the present brick-built library erected in its place, any remains of the open undercroft were incorporated into the library building. (3, 4)

The following text is from the original listed building designation:
1. 944 THE CATHEDRAL PRECINCTS
Prior's Chapel TR 1557 NW 5/1F
I
2. Cl260. Only the open undercroft remains incorporated in the brick library (the Hawley garrison Library) of 1660.
Listing NGR: TR1513957952 (5)

<1> DOE (HHR) City of Canterbury Kent Sept 1973 63 (OS Card Reference). SKE40123.

<2> OS 1/500 1874 (OS Card Reference). SKE48131.

<3> Willis, R., 1868, 'The Architectural History of the Conventual Buildings of the Monastery of Christchurch in Canterbury' (Article in serial). SKE30206.

<4> Blockley, K., Sparks, M. & Tatton-Brown, T., 1997, Canterbury Cathedral Nave, Archaeology, History and Architecture (Monograph). SKE29723.

<5> English Heritage, List of Buildings of Special Architectural or Historic Interest (Map). SKE16160.