families of Kennedy, Otterburn, and Preston. To
commemorate other benefactors, on the demi-pillar, on the north side of
the eastern window, we have the arms (three cranes _gorged_) of Thomas
Cranstoun, chief magistrate of Edinburgh in 1439 and 1454; on the south
side, those of Napier of Merchiston, Provost of Edinburgh in 1457--a
saltier engrailed, cantoned with four rosettes.[261] (2) The heightening
of the choir and the introduction of a new clerestory were also carried
out shortly after the middle of the fifteenth century, the height of the
former choir being shown by the vault of the crossing, which it
doubtless resembled, and which was not altered at that time. The outline
of the old roof may also be observed against the east and west walls of
the tower--the raglet and a stepped string-course above it being yet
preserved, and being specially visible on the east side next the choir.
The beauty of the vaulting of the central choir aisle is noticeable when
contrasted with that of the side aisles.[262] The central crossing, with
its vault, was left unaltered, and still remains in the same position,
with its vaulting at the level it was raised to about 1400. It forms a
break between the nave and the choir, in both of which the vault has
been raised.[263] (3) The transepts were extended, their original length
being marked by breaks in the roof, where the vaulting terminates.

In a charter dated 11th January 1454-1455,[264] it is narrated that
William Preston of Gourtoun, after much trouble and expense abroad, and
aided by "a high and mighty prince, the King of France, and many other
Lords of France," had succeeded in obtaining an arm bone of the patron
saint, which he generously bequeathed to the church. The Town Council
were so gratified with the gift that they resolved to add an aisle to
the choir in commemoration of the event, and to place therein a tablet
of brass recording the bounty of the donor. This aisle was to be built
within six or seven years "furth frae our Lady isle, quhair the said
William lyis." It thus appears that the south aisle of the nave was
known as the lady chapel, and that Sir William was buried there. The
resolution was carried into effect, and a new aisle called the Preston
Aisle was constructed, south of the lady chapel. The Preston Aisle was
afterwards known as the Assembly Aisle. In carrying out the work the
south wall opposite the three westmost bays of the choir was removed,
and three arche