en taken
down to make way for the Lady-chapel in Gloucester and Norwich, and for
the Trinity chapel in Canterbury cathedral (fig. 1). The semicircular
aisle is said to have existed in the Anglo-Norman cathedral of
Winchester, but the eastern end being square, two chapels were arranged
filling the north and south ends, and an apsidal chapel projecting
beyond the east wall. This semicircular processional aisle with chevet
chapels was the favourite type of plan in the Anglo-Norman cathedrals,
and was followed up to about the middle of the 12th century, when the
English builders in some cases returned to the square east end instead
of the semicircular apsidal termination. The earliest example of this
exists in Romsey Abbey (c. 1130), where the processional path crosses
behind the presbytery, there being eastern apsidal chapels in the axis
of the presbytery aisle and a central rectangular chapel beyond. A
similar arrangement is found in Hereford cathedral, and exists in
Winchester, Salisbury (fig. 2), Durham, St Albans, Exeter, Ely, Wells
and Peterborough, except that in all those cases (except Wells) the
eastern chapels are square ended; in Wells cathedral the most eastern
chapel (the Lady-chapel) has a polygonal termination; in Durham (fig.
3), the eastern chapels are all in one line, constituting the chapel of
the nine altars, which was probably borrowed from the eastern end of
Fountains Abbey. It should be noted that in some of the above the
original design has been transformed in rebuilding; thus in St Albans,
Durham, York and Exeter cathedrals, there was no eastern ambulatory but
three parallel apses, in some cases rectangular externally. In
Southwell, Rochester, Ely and Chester, there was no processional path or
ambulatory round the east end; in Carlisle no eastern chapels; and in
Oxford only one central apse. In Ely cathedral (fig. 4) the great
central tower built by the first Norman abbot (1082-1094) fell down in
1321, carrying with it portions of the adjoining bays of the nave,
transept and choir; instead of attempting to rebuild the tower, Alan of
Walsingham conceived the idea of obtaining a much larger area in the
centre of the cathedral, and instead of rebuilding the piers of the
tower he took as the base of his design a central octagonal space, the
width of which was equal to that of nave and aisles, with wide arches to
nave, transepts and choir, and smaller arches across the octagonal
sides; from shafts in the