As in the Rochester siege, castle defenders did not sit idly by while an
enemy was digging a sap. Typically, archers sprayed the areas around a tun-
nel’s front end, hoping to pick of some of the diggers as they entered and
exited. h e defenders also learned to dig their own tunnels directly below
those of the attackers, thereby causing the upper saps to collapse before
they reached the walls.
In addition, major improvements in castle design occurred after
the start of the First Crusade in 1096. At the urgings of Pope Urban II,
thousands of knights and other European soldiers journeyed to what
are now Palestine and Israel. h eir objective was to free Jerusalem
and other local sites that Christians viewed as sacred from the control
of Muslim forces. During the expedition, the European i ghters
saw many Middle Eastern fortresses up close. h oroughly impressed,
they later carried numerous architectural concepts back to their homelands.
“h e results,” historian Frances Gies explains,
“were an astonishing leap forward to massive, intricately
designed fortresses of solid masonry.”29
Among these construction ideas that European
builders incorporated into new castles was the arrow
loop, also called a murderess. It consisted of a vertical
rectangular opening in a castle wall through which
skilled bowmen could shoot arrows at besiegers outside.
h ese archers were well protected by a clever feature.
h e outside of a loop was very narrow, so most
enemy bowmen were unable to shoot arrows into it. On the inside, however,
the loop sharply widened, allowing the defending archers ample
room to maneuver and i re.
Another potent new design concept was machicolation. It consisted
of a stone ledge or shelf that extended slightly outward from the top of
the battlements. Usually the shelf was drilled with holes through which
defenders dropped boiling oil or rocks onto attackers below.
Also incorporated into new castles was the drawbridge. A wooden
platform lying across the moat, it gave the defenders ready access to the
front gate during peacetime. Yet the bridge could be pulled upward during
a siege, making it extremely dii cult for the attackers to reach the
gate and employ a battering ram to break through it.