
An arrowslit (often also referred to as an arrow loop, loophole or loop hole, and sometimes a balistraria
) is a narrow vertical aperture in a
fortification through which an
archer can launch
arrow
An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty (and usually sharp and pointed) arrowhead attached to the front end, multiple fin-like stabilizers c ...
s or a crossbowman can launch
bolts.
The interior walls behind an arrow loop are often cut away at an
oblique angle
In Euclidean geometry, an angle is the figure formed by two rays, called the '' sides'' of the angle, sharing a common endpoint, called the ''vertex'' of the angle.
Angles formed by two rays lie in the plane that contains the rays. Angles are ...
so that the archer has a wide
field of view and
field of fire. Arrow slits come in a variety of forms. A common one is the
cross, accommodating the use of both the
longbow and the
crossbow. The narrow vertical aperture permits the archer large degrees of freedom to vary the
elevation and direction of their bowshot, but makes it difficult for attackers to harm the archer since there is only a small target at which to aim.
Balistraria, plural balistrariae, from balister, crossbowman
can often be found in the
curtain walls of medieval
battlements beneath the
crenellations.
History
The invention of the arrowslit is attributed to
Archimedes
Archimedes of Syracuse (;; ) was a Greek mathematician, physicist, engineer, astronomer, and inventor from the ancient city of Syracuse in Sicily. Although few details of his life are known, he is regarded as one of the leading scientists ...
during the
siege of Syracuse in 214–212 BC (although archaeological evidence supports their existence in
Egyptian Middle Kingdom
The Middle Kingdom of Egypt (also known as The Period of Reunification) is the period in the history of ancient Egypt following a period of political division known as the First Intermediate Period. The Middle Kingdom lasted from approximately ...
forts
A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to establish rule in a region during peacetime. The term is derived from Latin ''fortis'' ("strong") and ''facere'' ...
around 1860 BC). Slits "of the height of a man and about a palm's width on the outside" allowed defenders to shoot bows and
scorpions (an ancient siege engine) from within the
city walls.
[.] Although used in late Greek and Roman defences, arrowslits were not present in early Norman
castle
A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word ''castle'', but usually consider it to be the private fortified r ...
s. They are reintroduced to military architecture only towards the end of the 12th century, with the castles of
Dover
Dover () is a town and major ferry port in Kent, South East England. It faces France across the Strait of Dover, the narrowest part of the English Channel at from Cap Gris Nez in France. It lies south-east of Canterbury and east of Maidstone ...
and
Framlingham in England, and
Richard the Lionheart's Château Gaillard in France. In these early examples, arrowslits were positioned to protect sections of the castle wall, rather than all sides of the castle. In the 13th century, it became common for arrowslits to be placed all around a castle's defences.
Elements of fortification such as arrowslits became associated with high social standing and authority. As such, damaging them could be significant as an aspect of
slighting.
The successor of arrowslits after the advent of
gunpowder was the
loophole for
firearm
A firearm is any type of gun designed to be readily carried and used by an individual. The term is legally defined further in different countries (see Legal definitions).
The first firearms originated in 10th-century China, when bamboo tubes ...
s.
Design

In its simplest form, an arrowslit was a narrow vertical opening; however, the different weapons used by defenders sometimes dictated the form of arrowslits. For example, openings for
longbowmen were usually tall and high to allow the user to shoot standing up and make use of the bow, while those for crossbowmen were usually lower down as it was easier for the user to shoot whilst kneeling to support the weight of the weapon. It was common for arrowslits to widen to a triangle at the bottom, called a fishtail, to allow defenders a clearer view of the base of the wall.
Immediately behind the slit there was a recess called an
embrasure; this allowed a defender to get close to the slit without being too cramped. The width of the slit dictated the field of fire, but the field of vision could be enhanced by the addition of horizontal openings; they allowed defenders to view the target before it entered range.
Usually, the horizontal slits were level, which created a cross shape, but less common was to have the slits off-set (called displaced traverse slots) as demonstrated in the remains of
White Castle in Wales. This has been characterised as an advance in design as it provided attackers with a smaller target; however, it has also been suggested that it was to allow the defenders of White Castle to keep attackers in their sights for longer because of the steep
moat
A moat is a deep, broad ditch, either dry or filled with water, that is dug and surrounds a castle, fortification, building or town, historically to provide it with a preliminary line of defence. In some places moats evolved into more extensive ...
surrounding the castle.
When an embrasure linked to more than one arrowslit (in the case of
Dover Castle, defenders from three embrasures can shoot through the same arrowslit) it is called a "multiple arrowslit".
Some arrowslits, such as those at
Corfe Castle, had lockers nearby to store spare arrows and bolts; these were usually located on the right hand side of the slit for ease of access and to allow a rapid rate of fire.
See also
*
Loophole (firearm), a protected small opening to discharge a firearm.
*
Loophole
References
Bibliography
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External links
{{Fortifications
Castle architecture