would be a strong lateral thrust as well as vertical pressure,
and these were to be provided for. We shall see presently that all the
real beauties of this most interesting work were the outcome both of
the needs of practical structure and the requirements of ritual and a
ceremonial expression of the liturgy.

[Illustration: HISTORICAL SECTION FROM WILLIS'S ARCHITECTURAL HISTORY.
Original Elevation. Present Elevation. Two Bays of Retro-choir. (Scale
29'2 feet to 1 in.)]

[Illustration: THE CLERESTORY, NORTH SIDE OF NAVE. _From a photograph
by Mr. Francis Bond_. ]

It is not possible for us to discover exactly when the several parts
of the work undertaken after the fire of 1186-1187 were begun, nor
when they were finished. Of dates we have little knowledge, except
that of the dedication in 1199, the fall of two towers in 1210, and
the various indications of architectural activity at certain periods
given by the several dates mentioned in connection with donations,
bequests, and royal sanctions in the episcopal statutes and other
documents. These nearly all show that the time of greatest activity
was after 1186 and before 1250. If such a feat as has been mentioned
was performed at Canterbury between 1174 and 1184, was it not possible
also at Chichester? Then it becomes necessary to assume that the
structural alterations were continuing during the whole of the period
suggested; and this was so. Enough work had been done by 1199 to allow
of another dedication of the building. Seffrid II. had been bishop
from 1180-1204, and the register of Bishop William Rede, written one
hundred and sixty years later, explicitly states that Seffrid
"re-edified the Church of Chichester." This is a comprehensive
statement, but it might easily include at least the greater part of
the vaulting with some form of external roof. Such a change as this
involved the alteration of the nave and aisle piers, so that the
slight vaulting shafts of finer stone might be inserted in the older
masonry. The lower part of each of the piers of the nave arcade on the
side towards the centre of the church was re-faced with the same
material, and smaller shafts of Purbeck marble were introduced upon
the piers, replacing probably the heavy ones of an earlier date. These
shafts formed the support to a more delicate moulded member, which was
now substituted for the original and very simple outer order of the
original arch. A string-course of Purbeck marble was inse