To defend themselves, local leaders revived and improved ancient
techniques of fortification and assault. The castle builders (military enlii
gineers) and commanders of the Middle Ages continued the siege warfare
techniques developed by the Romans, modifying designs and equipment
to accommodate local traditions, geography, and materials. Every
increase in offensive power was met with greater strength or cleverness
by defenders.
Chapter 2 looks at the castle as a fortification. Medieval warfare consisted
of long sieges around a castle or town and relatively short battles
in the field, rarely involving a large army of more than 20,000 men. The
castle held the defensive position, and a well-built stronghold could be
taken only through extended siege. In many ways, the advantage lay with
the castle dwellers because the castle could be well provisioned and
staffed while the assembled feudal army had to live off the land. In the
hey-day of castle building, early armies consisted of a relatively undisciplined
force of men who were only required to serve a limited time, usually
forty days a year. Such men might be more interested in returning
to their own homes than they were in pursuing their lord’s cause and
maintaining a siege.
Having decided to invest (lay siege to) the castle, the aggressor’s strategy
would be to block off supplies and reinforcements, and then to attempt
to take the castle by force, only when negotiation, treachery, or
blockade and starvation failed. An assault on the castle was a slow affair
because the attackers had to go over, through, or under the walls and
then engage in hand-to-hand combat. To go over the wall involved the
use of scaling ladders or a mobile wooden tower called a belfry. When
moved into place, this tower allowed knights to climb the ramparts to
the wall-walk and then engage their equals in combat. A slower, but often
more effective, assault involved tunneling under the wall, causing it to
collapse. Finally, to breach the walls the attackers used battering rams
and stone-throwing machines, which were essentially very large catapults
(see Figure 14). The most powerful engine was the trebuchet (a giant
sling), which could throw huge stones with great force. None of these
siege engines have survived, but a team of twenty-first-century “re-enacters”
has built and tested the trebuchet and other engines with spectacular
results.
The mightiest castles of the eleventh and twelfth centuries were once
veritable war machines, although even a well-built castle could be taken
after a long siege by starvation or treachery. Castle walls and towers were
defensive structures to be smashed by ever-increasing firepower. For all
their imposing appearance, many castles stood for only a few years before
they were destroyed and left in ruins. From the tenth through thirteenth
centuries, castles functioned as military machines, but in the
fourteenth and fifteenth centuries their role changed almost completely,
and they were replaced by forts designed for artillery.