o the east of the church.
A narrow footway, bounded to the east by cottages and garden walls,
renders it impossible to photograph the east window of the choir. This
is a most interesting one; and has been figured in most books on
architecture. It consists externally of three lancets enclosed in a
peculiar way by weather moulding; this rises separately over the head of
each lancet, and between the windows runs in a horizontal line and is
continued to the square corner buttresses. Within this moulding, and
over the heads of each lancet, there is an opening pierced: the central
one is a quatrefoil, while the other two have six points. These openings
are a very early example of plate tracery, which was fully developed in
the Early Decorated style. This window belongs to the Early English
period, and may be dated about 1220. There will be occasion to refer to
this window again when speaking of the interior of the church. The south
choir aisle has a five-light east window closely corresponding to the
window of the north aisle, and on the south two three-light windows. In
these, as in the east aisle windows, the lights are carried up through
the heads. There is no doorway giving access to this aisle from the
outside.

The angle between the choir aisle and south transept is filled up with
the vestry and the library above it. The south wall of this projects
beyond the wall of the south transept. This vestry is of Decorated date,
possibly rather later than the other Decorated work in the minster. The
upper storey forms the library. Its walls are finished at the top by a
plain parapet which conceals the flat roof. At the south-western angle
is an octagonal turret staircase, capped by a pyramidal roof rising from
within a battlemented parapet, and terminating in a carved finial. This
is of Perpendicular character. From the sharpness of the stone at the
coigns it would seem that very extensive restoration, if not absolute
rebuilding, of the walls was carried on in this part of the church.
The south transept is rather shorter than that on the north side; but,
unlike it, all the walls up to the level of the window are of Norman
date. The string courses on the western side are worthy of close
attention. One which runs under the south window is continued round the
Perpendicular buttresses at the south-west angle, and then again joins
the original course on the western face and runs to within a few feet
of the nave aisle, where it abrupt