De Leiâ’s church clearly terminated at the existing east wall of the presbytery and aisles, and apparently at the time of the rebuilding occasioned by the fall of the tower in 1220, no attempt was made to lengthen the church eastwards. It is not unlikely, however, that shortly before the time of the earthquake of 1248 a Lady Chapel or retro-choir was contemplated and even begun, but discontinued. As we see it now it is also not improbable that the original plan may have been followed, with many changes in detail in the succeeding centuries. The aisles continuing those of the presbytery are connected by a sort of retro-choir or ambulatory--embracing the space now occupied by Bishop Vaughan’s Chapel between it and the east wall of the presbytery. This is all Early English, _i.e._, thirteenth century, work. Bishop Martyn (1290-1328) completed the present ground-plan by adding his Lady Chapel. Bishop Gower (1328-1347), the Menevian Wykeham, raised the north and east walls of the north chapel aisle and rebuilt the south and east walls of the south aisle from the ground, probably on Early English foundations. Also, this aisle was projected a few feet in an easterly direction and many changes made in the Lady Chapel, where Gower founded a charity in 1334. Bishop Vaughan (1509-1522) appropriated the space east of the presbytery which was described[59] as “vilissimus sive sordidissimus locus in totâ ecclesiâ,” and converted it into the beautiful chapel which bears his name. Previous to this we can find no early references to this space which was walled in north, [Illustration: ROOF OF BISHOP VAUGHAN’S CHAPEL.] south, east, and west (according to Freeman) and may previously never have been roofed. With regard to this numerous suggestions have been made which do not seem entirely satisfactory. At any rate the east windows of the cathedral were glazed and required light, which we venture to suggest may have been obtained from the open passage left for pilgrims to reach the ancient recess in the east wall, which is apparently _in situ_ and bears unmistakable marks of having been polished by use. And, that the remainder of the space was screened off and roofed for the immurement of a recluse, who could perhaps watch unseen the movements of the pilgrims. It must be remembered also that stealing relics carried its own absolution. This might account, too, for its filthy state which necessitated the four pence of 1492[60] to clean. In those days an unusually large sum. In making this Trinity Chapel, Bishop Vaughan blocked up the lower east windows of the cathedral and probably added the upper tier shown on p. 36, and then added his fan-traceried roof and other ornaments.