THE CYLINDRICAL KEEP, _c._ 1170-1250
The latter part of the twelfth century and the earlier portion of the
thirteenth was marked by the introduction of the Cylindrical Keep,
forming a transition or connecting link between the Shell and the
Rectangular Keeps of the previous period, and the remarkable development
of castellation which occurred in the thirteenth century. The latter,
however, must not be considered in the light of a sudden revolutionary
change, inasmuch as many indications occur in the castles of the twelfth
century which exhibit a tendency to break through the conventionalism
then prevailing, and to produce works of a more complex character,
suited to the progress in military methods of attack. The introduction
of the Cylindrical Keep was one of these innovations; although it did
not remedy the great fault inherent in Keeps generally, viz. that of
impotence with regard to driving off the besiegers, yet it furnished a
method which enabled the builder to effect a considerable economy in
material and labour, while at the same time affording that strenuous
passive resistance to assault which characterised the former styles. It
is probable that King Henry II. was chiefly responsible for the
introduction of the Cylindrical Keep, as by reason of his French birth
he was acquainted with a number of foreign castles having citadels built
upon this plan. These Cylindrical Keeps were likewise known as Donjons
and Juliets, and attained to a degree of perfection upon the Continent
which was never reached in the British Isles. The example at Coucy is
probably the finest abroad.
The advantages which may be claimed for the Cylindrical Keep, apart from
its lessened cost of construction, are the increased solidity, and the
great difficulty in breaching it, or bringing it down by a mine. By
vaulting each floor the resistance of the structure was increased; by
enclosing the upper part in a similar manner also, the danger of fire
from incendiary missiles launched upon the roof was practically
nullified. A disadvantage, however, lay in the fact that the besieged
could not concentrate a discharge of missiles against assailants at one
part of the base without exposing themselves to the enemy's archery.
This was to a great extent rectified by the bretasche, which, though in
use previously, became established as a regular defence at this period.
These were timber galleries encircling the outer part of the tower at
its summit, supported in position by strong beams of wood inserted in
holes made for the purpose, and strengthened by struts resting upon
corbels. Upon this foundation a wooden gallery was built, covered in by
a sloping roof resting against the walls, and generally enclosing the
summit of the wall. In suitable places the gallery was loopholed for
archers and cross-bowmen, while through openings in the floor stones and
other missiles could be dropped upon assailants at the foot of the Keep.
It could be entered from the battlements behind, where stores of
ammunition were placed.
At times two bretasches were in use, one above the other; the upper
projected a greater distance from the walls so as to avoid injury to
the lower. The unfinished appearance of the tops of many towers can be
explained by their having been covered with a bretasche in former times,
although this defence was not kept in position permanently but usually
built upon the approach of danger. The machicoulis and alurs of a later
date were imitations in stone of the wooden bretasche. At Coucy these
defences were placed about 180 feet from the ground, and the nerve
displayed by the defenders working at such a giddy height excites
admiration.
The introduction of machicolation proper into England occurred in the
latter part of the thirteenth century and became a prominent feature at
that period. The faults inherent in the bretasche were the feeble
resistance which it offered to missiles launched from the mangonels of
the besiegers; the destruction of one part by a well-aimed stone would
naturally expose the remaining defenders to archery, besides seriously
weakening the rest of the structure, which depended to a great extent
upon its continuity for safety.
Another weakness was the perishable nature of the material, which
required constant renovation and addition, and to this circumstance
may be attributed the fact that examples of the true medieval bretasche
are extremely rare at the present day. A fragment remains over one of
the gates at Coucy, while the position of the main beam may be seen upon
the outer gate of Leeds Castle. At Norham Castle a small doorway appears
in the upper part of the square Keep, the conjectured use for which is
that it gave access to the bretasche. In many castles of the twelfth
century still remaining a line of small openings in the outer wall at
the top is visible; they indicate the position of the former bretasche,
and are caused by the removal of stones for the insertion of the
projecting beams. Notwithstanding the advantages inherent in the
Cylindrical Keep, which prompted their erection in many parts of France
and other parts of the Continent, we do not find one example forming an
integral part in a British Castle of the first class.
[Illustration: CARNARVON CASTLE. CARNARVONSHIRE.]
Cylindrical Keeps were not always of a stereotyped form, and among the
comparatively few erected in England there is marked diversity in
detail. Launceston, for example, really consists of a triple defence;
two outermost rings of walling, one of which is a dozen feet thick and
nearly 30 feet in height, effectually prevent any attempt at mining the
Keep proper, which stands a few feet within the second ring. It is now
only a shell, but timber flooring once divided it into three stories.
The walls are nearly 50 feet in height, about 10 feet thick at the base,
and stand in a ring whose diameter is nearly 20 feet. The open spaces
around the Keep were formerly covered by roofing.
Richard, King of the Romans and brother of Henry III., is generally
credited with raising the Launceston Keep and also the companion one at
Restormel. The Keep at Barnard Castle is remarkable for the huge
projecting triangular spur, which, springing from the soil, rises to
within a few feet of the parapet. The floors were vaulted. This circular
Keep is about 50 feet in height and 40 feet wide. Pembroke Keep, on the
other hand, rises without buttress or spur or concentric walling
straight from a battering base at the ground-level to a height of about
70 feet to the spring of the vaulted roof. It trusted apparently to the
enormous thickness of its walls, 20 feet at the base, to defy any
attempts at mining.
_Conisborough Castle_ possesses the most remarkable Keep of the
cylindrical type in the British Isles, both by reason of its
extraordinary plan and rare contour. It is a gigantic cylinder nearly 70
feet in diameter, and tapering upwards to a height of over 90 feet. Upon
the exterior six enormous buttresses are arranged symmetrically round
the face, projecting 9 feet from the surface and being 16 feet wide
where they support the cylinder. They diminish in width, however, as
they recede from it. These buttresses are carried up the whole height of
the Keep, and thus, combined as they are with a massive base of masonry
upon which the tower stands, and forming an integral portion of the wall
which is about 12 feet thick, we have what is probably the most
efficient protection against the deadly mine ever devised as a
protection to a British Castle. It may be compared to six enormous
spurs, the blowing up of one or even two but little affecting the
stability of the remainder.
[Illustration: GROUND PLAN OF CONISBOROUGH KEEP.]
[Illustration: CONISBOROUGH.]
The entrance to the Keep is only a small square aperture placed in the
first floor and approached by a long flight of steps in which at one
time a drawbridge occurred. The ground floor contains the well and is
entered by means of a trap-door in the vaulted ceiling. The buttresses
are excavated in places to form chambers, and in one is situated the
oratory described by Scott in _Ivanhoe_. It is beautifully vaulted in
the Early English style, with carved capitals and bases to the
supporting shafts. This grand relic of the feudal period was probably
built in the reign of Richard I. by Hamelin Plantagenet, the natural
brother of King Henry II., who had married into the de Warrenne family,
the rich Earls of Surrey.
Another variety of the Cylindrical Keep was that at Orford, in Suffolk,
which possessed a cylindrical shaft similar to that at Conisborough, and
was supported by three minor towers symmetrically arranged and carried
above the battlements. This Keep was protected at the base by a massive
wall with a ditch between the wall and the Castle base, and probably
suggested the Conisborough Keep and also that at Warkworth, while those
at Wallingford, York and Pontefract approximated to the same ideal.