Castle Arrowslits *Arrow Loops

Castle arrowslits are also known as arrow loops, loopholes, balistraria, and archerère. Basically, slits were created in fortified structures such as castle walls for archers to fire arrows or bolts through at besieging enemy forces. Arrowslits are narrow vertical apertures in castle walls that commonly formed a cross shape!

Arrowslits had to be narrow to protect defending archers, commonly there was also a horizontal line, these openings formed a cross shape, and circular-shaped openings could also be added which created a larger firing point for the archers defending the castle.

Windsor Castle Arrow Slit

Inside View of Arrow Slit or Arrow Loop *Windsor Castle

Crossbowman can launch bolts through a castles Arrowslits *Arrow loops

Crossbowman can launch bolts through a castles Arrowslits *Arrow loops


Castle arrow slits or loops were a clever design as the stone in the castle wall that surrounded the arrow slit hole was commonly angled to give archers a higher level of possible shot angles. These oblique angles allowed the castle archer to be able to move around the arrow slit and made it possible for an archer to fire his arrows at a wider target than would have otherwise been possible.

Crossbow weapons required a low arrow slit as they were easier to load and fire from a crouching position, whereas longbows were very long and the longbowmen needed to stand upright, this determined that the arrow slit would be much longer and possibly wider as well.

Castle Arrow Loops/Slits Fast Facts

  • The Length of Arrow slits varied but could be up to 9 feet in height to accommodate longbowmen weapons.
  • Crossbows were fired horizontally from arrow slits, longbows vertically.
  • The cross shape formed by the vertical and horizontal arrow slits resembled a crucifix.

The bottom of an arrow slit opening was called a fishtail, behind the arrow slit was a recess that helped the archer to move into the space to get a better view and freed up some space for movement, this was called an embrasure.

Horizontal openings were later added as the archer had a limited field of vision and could not see the attackers unless they were in a very limited field of vision.

Arrow Slit History

It is believed that Arrow slits were first created in ancient times by Archimedes around 214BC. Arrowslits were also recorded in Greek and Roman literature and Art, however arrow slits seem to have gone out of favour for a period that incorporated the Norman invasion period.

The use of arrow slits as a defensive feature of medieval castles was re-established around the 12th century. In earlier designs, castle arrow slits were mainly vertical thin gaps in the walls and had a limited field of vision and each archer was in charge of defending a small section of the castle walls which was his responsibility.

As arrow slits became more advanced and the openings were better designed a medieval archer was able to defend a larger part of the castle wall and his vision was better and the angles that he could fire his arrows from were greater.

It wasn’t until around the 13th century that castle designers demanded that arrow slits should be positioned all around the castle and its walls.

  • Dover Castle was designed with a narrow arrow slit with limited vision.
  • Framlingham Castles also has a dated type of arrow slit with limited all-around vision.
  • The Château Gaillard in France also has a similar arrow slit design.
  • White Castle in Wales has more advanced arrow slits called “displaced traverse slots” that give a better defense.

Types of Castle Arrow Slit

There were various arrow slit shapes also called arrow loops and other names.

The basic arrow slit shape was a thin vertical line, the limitations of this original arrow slit shape led to the creation of an added horizontal line that improved all-around vision. These horizontal lines were added at the eye height of the archers which gave the arrow slits the look of a religious cross, this type of arrow slit was called a Balistraria.

Displaced transverse slots or slits were another design that helped to protect the archer inside the castle by creating a smaller target for the attackers, these were offset slits that worked well.

Embrasures built into the castle wall design could allow several archers to fire from the same arrow slit at the same time, this made rapid-fire arrows on the enemy attackers possible.

We hope you found this article on arrow slits, arrow loop, and loopholes factual and informative, we suggest you look at our other articles in the castle parts section that will help you expand on your knowledge of castle arrow slits and give you a greater all-round understanding of arrow slits and castle defenses.