THE PROGRESS OF ATTACK AND DEFENCE
The earthwork fortifications, the progress of which we have traced up
to the Norman conquest, were of a very simple kind. It is obvious that,
in the history of military architecture, any improvement in defence
is the consequence of improved methods of attack. The stone-walled
town of the middle ages, the castle or private citadel, with its
curtain wall and the subdivision of its enclosure into more than one
bailey, succeeded the palisaded earthwork as a natural result of the
development of the art of siege. Against an enemy whose artillery was
comparatively feeble the stockaded enclosure was effective enough:
slingers and bowmen, working at close quarters, might do damage to the
defenders, but the palisade on the bank, divided from the besiegers by
a formidable ditch, was proof against missiles launched against it by
individuals, and could be carried only by a determined rush, or if it
were not sufficiently protected against fire. Modern warfare against
uncivilised tribes has shown that a stronghold defended by a thick
hedge is a serious problem to a besieging force. If, under modern
conditions, the stockade is a barrier to troops equipped with powerful
firearms, the difficulty which it afforded to the early medieval
warrior is obvious.
The age of firearms, however, which brought the death-blow to medieval
siegecraft, was long in coming; and meanwhile the progress of the
science of attack depended upon the improvement in methods which could
be employed only in close proximity to the besieged stronghold, or
within a very limited range. Engines for hurling stones or javelins
increased in size and strength. Devices were brought into play for
scaling or undermining the defences of the town or castle. The attack
was directed against the defences rather than against the defenders.
A casual stone might do injury to the medieval soldier, or an arrow
might pierce between the joints of his harness; but his armour, which
became more heavy and more carefully protected as the chance of risk
from such missiles increased, made loss of life in the course of a
siege a misfortune rather than an inevitable contingency. His first
anxiety, therefore, was to make the defensive works which sheltered
him impregnable. As the enemy multiplied his designs against the
palisaded enclosure, the palisade gave place to the stone wall; as
the enemy’s means for prosecuting his attempts increased in power,
the wall increased in height and strength; and at last, during the
transitional epoch in which firearms gradually superseded the older and
more primitive weapons of attack, the wall presented to the besieger
a thoroughly guarded front which rendered his medieval siege tactics
obsolete, and called for new developments in his craft.
The progress of fortification under these conditions will be the
subject of the remaining chapters of this book, with special reference
to the castle, in the defences of which the military engineers of the
middle ages displayed the epitome of their science. Before we proceed,
however, to the growth of the stone-walled castle, some description is
necessary of the improvement in siege-engines and methods of attack by
which its development was governed. It must be kept in mind that the
siegecraft of the middle ages advanced upon lines that were by no means
new. Its engines, its devices for breaking down or scaling walls and
towers, were not new inventions, but relics of Roman military science.
With the decay of the Roman power in western Europe, these materials of
warfare, unknown to the Teutonic conquerors of Britain, had fallen into
disuse. Preserved in the east by the Byzantine empire, the inheritor of
Roman civilisation, they became familiar to the barbarians who overran
Europe in the dark ages; and their revival in the parts of Europe most
remote from the historic centres of Roman influence was due in no small
measure to the adoption of traditional siegecraft by the invading
tribes which had come into conflict with Byzantine strategy. So far as
England is concerned, the first advance in the art of attack was the
direct result of the Norman conquest; while subsequent improvement in
western Europe generally was primarily due to the knowledge of eastern
warfare gained during the Crusades. A slight retrospect, under these
conditions, is desirable, which will give us some insight into the
methods of siegecraft during the period of whose strongholds and art of
fortification we already have seen something.
Many classical texts, from the time of Cæsar to the latest days of the
western Empire, supply us with authority for Roman military methods.
No passage throws fuller light on their siege practice than Cæsar’s
description of his siege of Alesia in Burgundy, the hill fortress
occupied by Vercingetorix.[65] The lines which were first drawn round
the stronghold by Cæsar were eleven miles in circuit, and communicated
with three camps, on hills of a height equal to that of the hill of
Alesia. Along the lines there were twenty-three _castella_, small
forts to hold pickets, and temporary examples of the type of which
the “mile-castles” of the Roman wall were permanent instances. The
stubborn resistance of Vercingetorix and the prospect of the arrival of
a relieving army, however, gave Cæsar occasion to elaborate his lines,
the character of which is very minutely described. They consisted of
an earthen bank with a ditch 20 feet broad, 400 feet in front of it
on the side towards the besieged stronghold. The ditch was dug with
perpendicular sides: its distance from the bank was a precaution
against sudden attacks of the enemy, and placed the bank out of the
range of casual missiles. The space between the bank and ditch was not
a level “berm,” but was furrowed by two ditches, 15 feet in breadth
and depth, of which the inner was wet, the water of the neighbouring
streams being diverted into it. Behind the inner ditch rose the earthen
_agger_ or bank, to the height of 12 feet. The _vallum_, the rampart
on the top of the _agger_, was of a type common in early warfare and
for many centuries later, consisting of a breastwork of interlaced
twigs stiffened by a row of palisades. The hurdles of the breastwork
were finished off with battlement-like projections: at intervals
there were tall uprights with forked tops, which were called _cervi_
or “stags,” and acted as _chevaux-de-frise_ along the whole rampart.
There were also towers, obviously temporary constructions of timber,
at distances of 80 feet from one another. This, however, was not
enough. Cæsar aimed at holding his lines with as few men as possible,
so as to allow the rest to do the necessary foraging at a distance. He
therefore proceeded to sow the approach to the lines with pitfalls.
Five ditches, 5 feet deep, were dug out and filled with upright stakes
sharpened to a point and fastened together at the bottom by continuous
cross pieces. In front of these were three rows of pits, 3 feet deep,
arranged in a series of _quincunces_ or saltires: in these were placed
smooth sharpened stakes, so that little more than their points stuck
out of the ground, and the pits were then covered over with twigs and
brushwood. The eight rows formed by these obstructions were each 3
feet apart. The whole arrangement, producing the effect of a row of
fleurs-de-lys, was called _lilium_: to the stakes the soldiers gave
the name of _cippi_ or “grave-stones.” On the opposite side of the
_vallum_, where an attack from a relieving army was expected, a similar
arrangement was made. Also, in front of the _lilium_, wooden cubes
with hooks fastened into them were hidden in the ground, bearing the
appropriate name of _stimuli_.
Cæsar’s method of besieging Alesia was dictated by the probability
that, with an enemy on both sides, he would have to stand a siege
himself. After a doubtful battle, the Gallic army of relief made a
night attack on the lines, in which they found to their cost the
effectiveness of Cæsar’s death-traps. They brought with them hurdles,
with which to help themselves across the ditches, and scaling ladders
and grappling hooks, with the help of which they might climb or pull
down the rampart. Their weapons were slings, arrows, and stones, to
which the Romans replied with extemporised slings and spears. They
suffered two repulses, and then turned their attention to the weakest
of Cæsar’s camps, while Vercingetorix left Alesia to attack the
rampart. His force brought hurdles with long balks of timber to form a
footway across them, mantlets, or coverings under which an attacking
party, sheltered from Roman missiles, could undermine or make a breach
in Cæsar’s earthwork by the use of a bore, and hooks with which to cut
down the rampart on the top of the earthen bank. The attack was long
and determined. The Gallic pioneers filled up Cæsar’s fosses, so far
as they could, with earth, and themselves raised a mound from which
his devices of defence were easily seen. Where his lines were on level
ground, they were too formidable to attack: on the steep slopes of the
hills, on the tops of which his camps were pitched, there was more
chance for an enemy. Here the fiercest fighting took place: the towers
of the _vallum_ were assailed with javelins, the ditch was filled, and
an attempt was made to tear down the palisade and breastwork. Labienus,
unable to hold the lines, sent a message to Cæsar, whose intervention
with his cavalry turned the day and brought about the total defeat of
the Gallic army and the surrender of Vercingetorix.
The account of the siege of Marseilles by Gaius Trebonius in B.C. 49
gives us many of the methods employed by the Romans, and by Byzantine
and medieval engineers after them, in the siege of a walled town.[66]
Marseilles was no mere hill stronghold like Alesia: it was a strongly
fortified seaport town, well equipped for war with engines which hurled
pointed stakes 12 feet long against the besiegers, as they threw up
their earthen bank round the landward side of the city. Trebonius had
to make the line of penthouses (_vineæ_), by which his pioneers were
protected, of more than ordinary thickness to withstand these missiles.
In advance of the bank, a body of men, sheltered by a large penthouse
(_testudo_) levelled the soil. While this leaguer was established on
the landward side, Brutus gained a naval victory over the Massiliotes,
who nevertheless continued to hold out against the besiegers. The
right wing of the Roman army was especially open to attack from the
city; and on this side the besiegers built a tower of brick, to serve
as a base of operations and a refuge from attack. This tower, which
was raised to a height of six stories, was built by workmen who were
sheltered by hanging mantlets of rope. A roof was made of timber,
covered with a layer of bricks and puddled clay, to protect it against
fire, and with raw hides, to make it proof against darts and stones.
As the tower grew, this roof, from which the rope mantlets depended,
was raised by levers and screwed down as a covering to each story in
succession. When it was nearly completed, a wooden penthouse known as
the mouse (_musculus_) was constructed, consisting of a gallery 60 feet
long, with a gabled roof, which was covered, like that of the tower,
with bricks, clay, and hide. This was moved forward on rollers to the
nearest point in the city-wall. It withstood the huge stones which were
cast upon it; lighted barrels of pitch and resin, hurled from the wall,
rolled off its sloping roof and were pushed to a safe distance by the
men inside, armed with poles and pitchforks. Covered by their friends’
fire from the brick tower, the soldiers in the mouse were able to sap
with their levers and wedges the foundations of the tower on the wall,
and managed to effect a breach. The defenders submitted, and asked for
a truce until Cæsar arrived; but, taking advantage of the interval,
they made a treacherous sally from the city, and, aided by a favourable
wind, burned down the besiegers’ constructions, including the mouse
and the brick tower, and destroyed their machines. Trebonius, however,
lost no time in constructing, instead of his earthen bank, a strong
wall of countervallation, composed of two parallel walls of brick,
each 6 feet thick, with a timber floor above. This quickly brought the
defenders to their senses, and they reverted to their old conditions of
peace. In this account the devices which play the chief part are met
again in numberless medieval sieges. The lines of countervallation,
the successful sapping operation, appear, for example, in the tactics
of Philip Augustus: the besiegers’ brick tower is met again in William
Rufus’ timber castle at Bamburgh: the engines of war and the protected
penthouses are commonplaces of medieval warfare.
The bare record of the Anglo-Saxon Chronicle throws little light to
speak of upon the strategy or military skill of the Danes. Nor does the
lyric form of the songs which celebrate the fight at Brunanburh and
the battle of Maldon allow of that definiteness of detail which the
student requires. More definite, although not unencumbered by rhetoric,
is the account which Abbo, the monk of Saint-Germain-des-Prés, gives
of the siege of Paris by the Northmen in 885-6.[67] The city of those
days was confined to the isle still known as La Cité, and was united
to its suburbs on the mainland by two bridges, where now are the
Pont-au-Change and the Petit-Pont. The approach to each bridge was
guarded, on the mainland, by a tower or _tête-du-pont_. The attack of
the Normans was directed against the northern tower, the construction
of which had not been finished. It is curious to notice how they
concentrated themselves on single points in the defence, neglecting
the prime necessity of closing all lines of communication to the
defenders. They came up to the tower with their ships, which were seven
hundred in number, not counting sailless boats, battered it with their
engines, and hurled darts at its defenders. The tower was shaken, but
its foundations stood firm: where the walls threatened to give, they
were repaired with planks of timber, and the tower was raised by these
wooden additions during a night to one and a half times its former
height. At daybreak the Northmen again began the attack. The air,
says Abbo, was full of arrows and stones flung from slings and from
the _ballistae_ or hurling machines. During the day the heightened
tower showed signs of succumbing to the enemy’s fire and their mining
efforts. Eudes, the brave defender of the town, poured down a mixture
of burning oil, wax, and pitch, which quenched the enthusiasm of the
besiegers, and cost them three hundred men. On the third day, the
Northmen established their land camp on the northern bank of the river,
near the church of Saint-Germain-l’Auxerrois. The camp was probably a
_geweorc_ such as they wrought by the Thames or the Ouse, but it was
girt, not with an earthen rampart, but with walls of clay mingled with
stone. From this centre they cruelly ravaged the surrounding country
during the remainder of the siege. Having thus established their
base of operations, they returned to the attack of the tower. Their
devices were the common devices of Roman warfare, which naturally would
recommend themselves to the assailants of the dying Roman civilisation.
We hear of the three great battering rams which they prepared, and
moved up against the walls under the shelter of wooden penthouses
on wheels, of the bores brought up to undermine the tower by men
moving under wicker mantlets covered with raw hides, of the _mangana_
or stone-throwing machines used by the defenders, and of the forked
beams let down from the tower to catch the heads of the battering-rams
and render them powerless. Some of the Northmen worked at filling up
the ditches with whatever came to hand, earth, leaves, straw, meadow
grass, cattle, even the bodies of captives. Still the city held out,
and Eudes managed to slip through the enemy’s lines and reach Charles
the Fat with a request for relief. On his return the Northmen tried to
intercept him: he got back safely into Paris, while a relieving force
attacked the enemy and drove them back on their ships. When Charles
the Fat arrived he established his camp on the southern slopes of
Montmartre; but he was content, after a general attack upon the city
had failed, to let the Northmen go, taking with them an indemnity of
seven hundred pounds, and promising to leave the kingdom in March.
They, however, made an attempt to reach the upper Seine in boats, as
the larger vessels could not clear the bridges, and so proceed to
pillage Burgundy. Their purpose was discovered: the defenders of Paris
launched arrows at them from the walls, and a chance dart killed their
pilot. For a time their onward course was checked, but a series of such
assaults could not be sustained by the French. Eudes, elected king,
neglected the conflict, and gave words for deeds. “Their barks,” says
Abbo, “were in crowds on all the rivers of Gaul.” He ends his poem with
a call to France to give proof once more of those forces which she had
used in the past to conquer kingdoms more powerful than herself. “Three
vices,” he cries, “are causes of thy ruin: pride, the shameful love of
pleasures, the vain lust of gorgeous apparel.” The same words might
have been said to the English a hundred and twenty-five years later,
when Swegen and Thurkill were gripping London between their two armies.
A short passage in the Anglo-Saxon Chronicle affords some help to the
question of Danish strategy. London bridge, like the two bridges of
Paris, was an obstacle to the long Danish ships with their sails. In
1016, however, the Danes managed to drag their ships round the south
side of the bridge, apparently by making a ditch on that side of the
river. They then proceeded to make entrenchments about the city, their
headquarters being thus removed above bridge. There is no reason to
doubt that the London which they thus beset was a stone-walled city,
the Roman Londinium which Alfred had repaired. So was Paris, and so
were a large number of the towns of France, whose walls had been set
in repair by their bishops or lay lords. We read of Saint Didier,
bishop of Cahors 630-55, that he “enlarged, built, and made strong
Cahors with abundant labour, and a notable work of defence, fortifying
gates and towers with a girdle of walls compacted of squared stones.”
In the next century the Saracen invaders of southern France restored
the Roman walls of Narbonne, and checked the advance of Charles Martel
into Spain.[68] But for the many instances in which the fortifications
of Roman cities in France played a part in the warfare of this troubled
epoch, there are few in England. The _burhs_ of the Danish wars were,
with the exception of London, Towcester, Colchester, and a few more,
not stone-walled cities of Roman foundation, such as those which in
France were the natural prey of the Norman marauders, but villages or
small towns which had grown into existence for the most part since
the Saxon conquest, and owed their strength to walls of timber. In
France military art, as regards both fortification and siege-craft, was
altogether on a higher plane. The break of continuity caused by the
extinction of Roman civilisation in England produced a stage in the
development of attack and defence to which contemporary French history
affords no parallel. It is not till a later period that the finished
methods employed by both sides in the siege of Paris were used in
English warfare.
The cases hitherto quoted refer to sieges of towns; and, as we have
seen, the castle or private fortress which plays so prominent a part
in medieval strategy was the result of the growth of the feudal
system, and takes its place in history at a comparatively late period.
A fortified town of Roman origin possessed its _arx_ or citadel:
this was, as it were, the keep of the walled enclosure, to which the
defenders could retire if the outer defences of the town were taken. A
castle, however, was a distinct enclosure, which frequently occupied
a portion of the area of a walled town, but had its own outer lines
of defence before the keep could be reached. The Norman conquerors of
England, regarding the castle as the main seat of defence and object
of attack, directed their attention to its fortification; and thus the
defence of the town or village in or near which the castle stood became
of secondary interest. We usually find that, where a castle forms
part of the defences of an English walled town, the castle has been
surrounded with a wall and provided with its necessary defences before
a wall has been built round the town in place of the earlier palisade.
In spite, however, of this change in the nature of the besieged
stronghold, the object of attack was still a fortified enclosure.
The methods of siege developed along the old lines; and the defences
applied to the castle were those which, on a more extended scale, were
applicable to the town.
The warfare of the eleventh and twelfth centuries was to a great extent
a succession of sieges of castles, by direct attack or by blockade. In
1083 William the Conqueror, besieging Hubert of Maine in the castle
of Ste-Suzanne, did not venture to attack the wooded precipice on
which the castle stood, but entrenched his army within earthworks in a
neighbouring valley. The blockade lasted three years, and the advantage
lay much on the side of Hubert, so that eventually the Norman army,
after a desperate attack had failed, withdrew.[69] The chief feature of
the blockade was the construction of an opposition castle,[70] a method
employed upon more than one occasion by William II., who, in 1088,
compelled Odo to surrender Rochester castle by making two _castella_
upon his lines of communication.[71] In 1095 William II. besieged
Robert Mowbray in Bamburgh castle. The great rock, with its girdle
of sea and marsh, did not lend itself to direct attack, and William
compelled its surrender by building a “new fortress,” which took the
form of a timber castle, probably of the ordinary mount-and-bailey
type, and was nicknamed Malvoisin, the “ill neighbour.”[72] From
this particular instance, the name of _malvoisin_ has been applied
generally, without sufficient reason, to the wooden towers which were
sometimes constructed to shelter a besieging force. As a matter of
fact, Malvoisin was merely one of many nicknames which were given, in
individual cases, to such besiegers’ castles,[73] and was no more a
generic term than is Château-Gaillard.
Until the end of the eleventh century, when the first Crusade
taught western warriors the use of more advanced siege-engines, the
methods of attack upon a castle seem to have been of a very simple
description. Earthworks defended by timber could be gained by a
rush and hand-to-hand fighting; while fire would always be fatal to
a wooden stronghold ill provided against it. The Bayeux tapestry
shows us none of those siege-machines which were employed more and
more frequently against stone castles during the next century; and,
although the Conqueror’s army seem to have employed an elementary
form of stone-throwing machine, handled, like the later cross-bow,
by individual soldiers, and other devices more familiar in later
times,[74] such machines can hardly have been common. It was, no doubt,
their growing frequency at the beginning of the twelfth century which
made stone walls imperative for the protection of a castle. We have
seen _ballistae_ and other siege-engines of Roman origin used by the
Northmen at the great siege of Paris in 885; but such engines were
certainly not in common use in western Europe before the period of
direct contact with Byzantine civilisation. Ordericus Vitalis mentions
the construction of such machines, a “belfry” on wheels and devices
for hurling large stones, by Robert of Bellême’s engineer at Bréval in
1093, as though they were a novelty, and says of the engineer himself
that his sagacious ingenuity had been of profit to the Christians at
the siege of Jerusalem.[75]
Suger’s detailed account of the attack made by Louis VI. upon the
castle of Le Puiset in 1111 may be taken as a fair description of the
methods employed by the besiegers and defenders of an ordinary castle
of earthwork and timber. The king brought numerous _ballistae_ to the
attack, but we have no indication as to their precise nature: the main
weapons employed were the bow, sword, and shield. The besieged came out
of the castle to meet the king; but, amid a hail of arrows from both
sides, were driven back through the main gateway, which was possibly,
as at Tickhill,[76] the only stone defence of the enclosure. From the
rampart of their stronghold, they hurled down wooden planks and stakes
upon the king’s knights. The besiegers, throwing away their broken
shields, made use of the missiles to protect themselves and force the
gateway. Carts laden with dry wood smeared with fat were brought up
to the doors, and a struggle took place, the royalists trying to set
the wood on fire, the defenders trying to put the fire out. Meanwhile
Theobald of Chartres made an attack on the castle from another quarter,
attempting to climb the steep scarp of the bailey. His followers,
however, were too hasty: many fell back into the ditch, while others
were surprised and killed by horsemen of the enemy, who galloped round
the defences of the castle to keep out intruders. The royalists had
almost given up hope, when a priest, bare-headed and holding before
him a piece of wood as an extemporised mantlet, reached the palisade,
and began to tear away the planks which covered the spaces between the
uprights. He was soon joined by others, who cut away the palisade with
axes and iron tools. The royal army poured into the castle, and the
defenders, taken between the entering force and Theobald’s men, retired
into the timber tower on the mount, but surrendered in fear. The king
burned the castle, but spared the donjon.[77]
The assault upon a stone castle or walled town was conducted by direct
attempts upon the walls themselves, for which movable machines were
necessary, and by throwing stones or inflammable materials into the
besieged enclosure from stationary machines. The chief engine used
directly against the walls was the battering-ram, an enormous pole,
furnished with an iron head. Hung by chains within a wooden framework
placed on wheels, it was brought up to the wall, and driven against
it again and again. The men who worked the ram were protected by
a pent-house with a rounded or gabled top, called the “tortoise”
(_testudo_), which covered the machine and its framework. The roof of
the “tortoise” was made very solidly, to resist missiles thrown from
the ramparts, and the whole was covered with raw hides or some other
incombustible material, as a precaution against fire thrown by the
defenders (69).[78]
[Illustration: Battering-ram protected by pent-house and mantlets]
While the ram delivered its blows upon the face of the wall, sappers
and miners, sheltered by a smaller pent-house, known as the “mouse,”
“cat,” or “sow,” made their attack upon the foundations with the bore
(_terebra_), a heavy pole with a sharp iron head, which slowly broke
up the stonework and hollowed out a cavity at the foundation of the
walls (70). This work was assisted by sappers, who, advancing to the
wall beneath the shelter of inclined frames of timber or wicker-work,
known as mantlets, which they wheeled in front of them, hacked away
the stone-work with picks. When a sufficient hollow had been made, the
miners underpinned the wall with logs, set fire to them, and retired.
This device was constantly used throughout the middle ages to effect a
breach, and was successful at Château-Gaillard in 1204,[79] and on
other occasions; but it obviously must have taken much time, and must
often have failed of its purpose.
Before, however, the movable engines could be brought to play upon the
stonework, it was necessary to fill up the ditch in front of the walls.
This work was done by soldiers, who, under the protection of mantlets,
flung into the ditch all the loose material on which they could lay
hands. When the Danes used their battering-rams against the northern
_tête-du-pont_ at Paris, the first thing which they attempted to do
was to fill the ditch, using even the dead bodies of their captives
when other material failed.[80] At Jerusalem in 1099, before Raymond
of Toulouse could bring up his “timber castle”[81] to the walls, a
deep natural hollow had to be filled. The work took three days and
nights: every man who put three stones into the hollow was promised a
penny.[82] Philip Augustus in February 1203-4 began his operations upon
Château-Gaillard by filling the ditch between the outer ward and his
lines, while his catapults played upon the masonry from a distance and
protected the workers between them and the wall.[83]
[Illustration: Bore protected by mantlets]
While the battering-ram, the bore, and the mine threatened the
stability of the walls, parties of the besiegers attempted to force
an entry into the stronghold. The simple method of bringing up fuel
to the main gateway, and burning down the door, was frustrated, in
process of time, by greater attention to the defences of the gateway,
and the reinforcement of its doors by herses or portcullises.[84]
Scaling-ladders were moved up against the walls: the daring spirits
who climbed these drew up with them other ladders, by which they could
descend into the enclosure. Another method of scaling walls was by the
movable “belfry,” a tower of several stories, in each of which a number
of men could be sheltered. The floor of the uppermost stage of the
tower was approximately on a level with the top of the ramparts, and a
drawbridge thrown out from it, when it was wheeled close to the wall,
formed a passage for the besiegers. The occupants of the lower stages
could mount by stairs to the top floor, and thus a considerable body
of men could come to close quarters with the defenders (72).[85] These
movable towers could be quickly constructed, where wood of sufficient
scantling was procurable. Philip’s belfries at Château-Gaillard
were composed of tree-trunks, untouched by the plane: all that the
carpenters had done to smooth them was to cut off the branches with
an axe.[86] In early instances of the employment of such towers, they
seem to have been chiefly used for bringing the small artillery of
the besiegers close to the walls. At Marrah in 1098, the Crusader
Raymond of Toulouse had a very lofty wooden “belfry,” of a height equal
to that of the towers on the town wall, made upon four wheels. Huge
stones were hurled and arrows shot from it upon the defenders of the
walls, and grappling-irons were thrust out to catch unwary persons with
their hooks. The walls were eventually climbed by scaling ladders of
the ordinary kind: if there was a drawbridge in connection with the
machine, it does not seem to have been used.[87] Antioch, earlier in
the same year, was entered by scaling ladders.[88] The belfry used
by Henry I. at Pontaudemer in 1123 was a movable tower, but was not
used for purposes of scaling. It was actually 24 feet higher than the
rampart: bow-men and arbalasters directed their arrows and bolts from
it upon the defenders, while others threw stones down from it.[89] Not
even at Château-Gaillard is there much reason to suppose that Philip
used his belfries to scale the walls. The miners and catapults did
the chief work, by opening breaches in the masonry of the outer and
inner wards: the middle ward alone was gained by an escalade, and this
was effected by a small body of men, who climbed through unguarded
openings in the substructure of the chapel, and so were able to unbar
the gates of the ward to the main body of the army.
[Illustration: Besiegers scaling walls from movable belfry]
The great siege-engines, capable of shooting stones or bolts,
which were often heated red-hot in an oven before delivery, from a
considerable distance, did their work from the background. The men who
looked after them were protected by a palisade, placed in front of the
engines; this was the case with Philip’s engineers at Château-Gaillard.
These machines are often indiscriminately called “stone-throwers”
(_petrariae_, _pierrières_) or catapults; and accounts of them differ
very considerably. It is clear that, in Roman and Byzantine warfare,
the two main types of engine were the stone-throwing machine, known
later as the mangon or mangonel, and the machine for shooting javelins,
known as _ballista_.[90] The first consisted of an upright flexible
beam between two solid upright posts. Cords were stretched from post
to post and wound round the beam. The beam was then drawn back with
the aid of winches and a stone placed in a hollow in its head; it was
then suddenly let go, so that the twisted cords slackened, and the
stone flew towards its mark, describing a high ellipse in its flight.
The force by which the _ballista_ was worked, depended, not on twisted
cords, but on the tension of the cord which joined the two extremities
of a great bow, and was attached to the movable grooved piece in
which the javelin was placed. The tension released, the javelin was
discharged. While the _ballista_ could be discharged with a definite
aim, the aim of the stone-throwing machine could be only general, and
its chief use was to cast stones which, by their elliptic flight,
dropped inside the walls of the besieged place.[91]
[Illustration: Engine for shooting javelins]
[Illustration: Stone-throwing engine]
The _ballista_, which was simply a huge bow, capable of shooting
enormous bolts by the tension of a horizontal cord, was developed
upon a small scale into the cross-bow or arbalast, which could be
carried and managed by one man. The cross-bow was invented, or at
any rate re-invented, in northern Europe towards the end of the
eleventh century, it was employed in the first Crusade, and struck
the Byzantines as a novelty.[92] The development of the larger
engines seems to have proceeded with a view to stone-throwing, and
combinations of the machines mentioned above may have been employed
for this purpose.[93] Viollet-le-Duc, in his elaborate reconstructions
of siege-machines, shows, for example, a mangon with a central upright
post, working on a pivot, in a slot near the top of which is fixed a
javelin. This post is strengthened by two diagonal beams fixed to the
back of the framework, which moves on the same pivot, at the foot of
the machine. Between these the flexible beam which propels the javelin
is fastened by a cord working through a pulley to a winch turned by
a man, and a bundle of cords is tightly twisted round the central
post and the beam (74). He also shows a large stone-throwing engine
on a wheeled carriage, which, in addition to an apparatus of twisted
cords held in place by a system of ratchet wheels, and bound round the
movable beam, has a cord stretched round the back of the beam, and
connected with two huge springs forming a bow. The centre of the bow
is a massive upright framework of wood, which acts as a buffer to the
beam, when it is allowed to fly forward and discharge the stone (74).
Minute as these reconstructions are, they seem to improve upon the data
supplied by medieval writers and the pictures in MSS. Guillaume le
Breton, the panegyrist of Philip Augustus, describes the stone-throwing
machine used at the siege of Boves in 1185, as a great sling worked by
several men, which threw immense rocks of great weight. The beam to
which the projectile was attached worked on an axis, and was dragged
backwards to the ground with ropes, and then set free.
[Illustration: Trébuchet or Slinging machine]
[Illustration: Trébuchet with ropes attached to counterpoise]
This description suggests that the beam, balanced on an axis, and
needing several people to attend to the discharge at one end, was
worked by a counterpoise at the other. This was the case with the
developed slinging machine, known as _trébuchet_. A pole, working on
a pivot between two upright stands, was weighted at one end with a
heavy wooden chest, filled with earth, which kept the pole, when not
in use, in a vertical position. To the other end was attached a long
sling, capable of containing large stones. When the tension of the
ropes which dragged the pole backwards and lifted the counterpoise was
released, the counterpoise fell heavily, bringing the pole abruptly
back into position, and the sling, describing a circle in the air, let
fly the stone when it reached the summit of the arc (75). Variations
of this form of catapult, which became general in the thirteenth
century, are found (76); the machine known as _cabulus_ which Philip
Augustus used with excellent effect against the strong inner wall
of Château-Gaillard, was possibly worked upon the principle of
counterpoise.
Against these modes and machines of attack the defenders of a castle
had to contend. The obvious means of defence was to oppose to the enemy
a thickness of wall which would be proof against the blows of the ram
or the slow labour of the pick. But even the very strong inner wall
at Château-Gaillard, which was constructed with the special object of
resisting these engines, yielded to the miners, reinforced by the
great slinging machine. In this instance the castle had undergone
a long blockade; its communications had been cut off some months
beforehand; and the garrison was greatly reduced in numbers. The lesson
of the siege was that against a persistent and well-conducted blockade
mere passive strength was of little avail. Here, too, the defenders,
driven back from one bailey to another, seem to have renounced the
opportunity of final shelter afforded them by the keep, and to have
made an attempt to evacuate the castle by a postern before they fell
into the hands of the enemy.
[Illustration: Aigues-Mortes]
[Illustration: Carcassonne]
Château-Gaillard, however, and the castles of its period will be
discussed in detail in the sequel. At present, we are concerned with
the direct methods employed to meet the attack of siege-engines
and attempts at escalade. Against the great catapults the besieged
were practically powerless. The use of such machines upon the walls
themselves was as dangerous to the stability of the masonry as their
use by the enemy, and hastened the chance of a breach: they could not
be employed from the interior of the enclosure, without endangering
the defenders on the rampart.[94] The summit of the rectangular
keep of the twelfth century was never constructed as a platform for
artillery: here, again, engineers probably feared the effect of the
constant vibration upon a flat wooden roof, and were content to conceal
their ridged roofs within high ramparts. The main arm of defence which
could be employed by the defenders was the cross-bow. Their superior
position upon the ramparts enabled them to throw down stones and
burning material upon the assailants engaged at the foot of the wall,
and the wheeled belfries formed a direct target for their arrows. The
ram could also be paralysed by letting down grappling-irons or beams
with forked heads, which gripped and disabled it; or sacks of wool or
earth could be lowered to meet its strokes. The assailants, however,
worked under their defences of pent-houses and mantlets, the solid tops
and sloping surfaces of which were specially devised against the shock
of stones and arrows; while, as we have seen, their coverings were so
protected that it was difficult for them to catch fire.
[Illustration:
Parapet defended by hoarding, showing elevation, section through
_hourd_ and _coursière_, and method of construction]
[Illustration: Laval]
The first improvements in defence, designed to meet an improved attack,
consisted in the protection of the ramparts. Behind the outer parapet
of the wall was the rampart-walk, a level path along the top of the
wall, which was sometimes protected by a parapet in the rear. From an
early date in stone fortification, it was customary to break the upper
portion of the parapet at intervals by openings called crenellations,
through which it was possible for an archer to command a limited part
of the field at right angles to the wall.[95] The crenellations,
however, were narrow compared with the unbroken parapets between them,
and, even in advanced examples of fortification like the ramparts
of Aigues-Mortes (77) and Carcassonne (78), these unbroken pieces
are still very broad, although they are pierced by arrow-slits. Even
allowing for an arrow-slit between each crenellation, the foot of the
wall could not be commanded from behind the parapet. In time of siege,
then, it became customary to supply the walls with projecting wooden
galleries, known as hoardings or brattices (_hourds_, _bretèches_),
which could be entered through the crenellations. The joists of the
flooring passed through holes at the foot of the parapet, and were
often common to the outer gallery and an inner gallery (_coursière_)
covering the rampart-walk. Both galleries had a common roof.[96] In the
floor of the outer gallery, between the joists, were holes, through
which missiles could be directed upon the besiegers at the foot of the
wall; while slits in the outer face were still available for straight
firing. The defenders of the ramparts were thus able to work under
shelter, with some command both of the field and the foot of the wall.
The defensive advantages of this scheme are obvious; but the galleries
were also liable, although the usual precautions for their covering
were taken, to destruction by fire, whether from arrows tipped with
burning tow, or the more formidable red-hot stones flung by catapults.
In any case, the catapults were a serious menace to their solidity.
[Illustration: Coucy; parapet of donjon]
The donjon and the towers of the _enceinte_ were also bratticed
at the rampart-level.[97] Indications of this practice are common
in military architecture abroad. The cylindrical donjon of Laval
(80), a work of the twelfth century, is covered with hoarding which
is supposed to be contemporary with the tower. The stone corbels
which carried the hoarding of the great thirteenth-century tower of
Coucy remain; and a row of plain arches pierced in the tall parapet
show how the gallery was entered from the roof (81). The somewhat
earlier round tower at Rouen was restored by Viollet-le-Duc on the
lines of Coucy, with a conical roof and hoarding. The inner wall at
Carcassonne and the curtain of Loches, among other examples, keep the
holes in which the joists of the hoarding were fixed; and the walls
of Nuremberg are still covered with inner galleries or _coursières_.
The practice of supplementing stone walls with timber defences lasted
till a late period; but, even before the end of the twelfth century,
corbelled-out parapets with machicolations appeared in isolated
instances. In subsequent chapters we shall see how military masons and
engineers applied their architectural skill to meet the problems which
siege-engines of greater strength and tactics more finished than those
of the past forced upon them. We have now to deal with earlier efforts,
which we have to some degree anticipated.