Hoping to thwart any attack launched against them, the builders of European
castles incorporated as many security features as they could into their
basic design, including ways to stop besiegers from getting over, under,
or through the walls and other defenses. Some of these features became
outdated when new tools for waging of ensive sieges were invented. h e
defenders then had to come up with ways to neutralize those new tools. In
turn, this stimulated the attackers to try to i nd still more ways to outsmart
the besieged, and so forth. Siege warfare in medieval Europe therefore contained
a kind of military arms race related to penetrating fortii cations on
the one hand and to maintaining their security on the other.
Few castles existed in Europe before the Battle of Hastings and the
Norman conquest of England. Afterward, most of the early fortresses were
motte and baileys, consisting mainly of small earthen mounds and wooden
stockades. Duke William’s initial intention in erecting these structures was
to use them as guard posts to watch over and control specii c regions.
A clear example of the ef ectiveness of this approach was William’s
i rst large motte and bailey, established at Berkhamsted, 25 miles (40 km)
northwest of London, in the late fall of 1066. Erected in only a few weeks,
the castle featured a motte about 40 feet (12 m) high. h e bailey was about
500 by 300 feet (150 by 91 m) in extent and surrounded by a tall stockade.
At least one water-i lled moat ran along the perimeter of the fence.
h is imposing structure, garrisoned by several hundred soldiers, was part
of William’s i rst major goal following the i ght at Hastings. He hoped to persuade
the Saxon nobles who then controlled London, and who still opposed
him, to surrender the city. Placing the castle beside the key road leading from
London northward into the Midlands (south-central England) was meant
to send a message to them. William knew that the native Saxons had no
large-scale military installations of their own and correctly reasoned that the
sudden appearance of such structures would intimidate the locals. As British
historian Geof rey Hindley puts it, the i rst Norman castles sent “an unmistakable
signal to a conquered people to heed the alien oppressor and robber
of their liberty.”24 h us, seeing the new motte and bailey at Berkhamsted,
along with other castles rising nearby, the nobles in London realized they
were outmatched. h ey soon surrendered to William without a i ght.
It appears that England’s new Norman ruler had planned all along to
eventually replace most of his motte and baileys with stronger, more permanent
stone versions. h is advanced castle-building
program began in the last decades of the eleventh century
and inl uenced builders across Europe. Archer Jones
describes the i rst Norman stone fortresses, which were
fairly small and simple compared to later versions: “h e
early Norman castle,” he writes, “concentrated almost all
of its strength in a single enormous tower known as a
donjon or keep.” h is impressive structure “combined
height and a maximum space inside with only a narrow
perimeter to defend. Defenders needed only men enough to man the battlements
and to drop things down on anyone trying to sap [dig beneath] the
base of the wall.”25
Most of the Norman stone keeps were square in shape. Each had a
small square turret—a defensive box or projection—rising upward from
the top of each corner. h e keep acted either as a secure residence for the
owner or a last refuge for the owner and other upper-class residents of the
area during an emergency.
Most often a narrow courtyard surrounded the keep. h at open space
itself was lined by tall defensive walls, often termed curtain walls. Inside
these barriers the builders installed workshops, stables, storerooms, and
living quarters for the soldiers who manned the defenses. Meanwhile, the
outer walls’ perimeter was frequently lined with a deep, water-i lled moat
intended to keep attackers away from the walls. Extra courtyards and sets
of defensive walls were added to many of the i rst stone fortresses in the
two centuries that followed, even while much larger and more complex
castles were built from scratch.