The Anatomy of a Castle – The Tower

Ashton's Tower from keep, Portchester Castle

Ashton’s Tower from the keep, Portchester Castle

A tower was a tall structure on the outer wall of a castle and most castles had more than one. None of them was as tall as the keep. Despite that, they were very much a sign of dominion in the early, Norman, castles. They were called donjons, from the Latin ‘dominor’ – to master, to rule over.

Originally towers were square. This made them fairly easy to build. Square towers were, however, vulnerable to mining. If the besieging army could send miners underground, they could cause a tower to collapse by setting fire to the wood that had been supporting the tunnel under a corner of the tower. The corners were weak spots.

Round towers were less vulnerable to undermining. In addition, it was more difficult to rest a ladder against a round tower, which meant that castles with round towers were less easy to storm.

When Edward I built his showpiece castle at Caernarfon, he built polygonal towers inspired by the towers of Constantinople.

Towers had arrow loops built into them allowing the defenders to shoot arrows or crossbow bolts at attackers whilst having some form of protection. The shape of the arrow loop allows the archer, or crossbowman, to cover quite a lot of the ground below the tower. There is room for them to move from side to side and up and down, but the part of the arrow loop presented on the outside is so narrow that opposing archers or crossbowmen would need a lot of skill to get an arrow through it.


Arrow Loop, Arundel Tower, Southampton

This is the same tower from the outside. You can see how narrow the arrow loops are. Any soldiers attacking this tower would have to shoot upwards as well.  In this particular instance, they’d probably have to do it from a ship, as the water used to come up to the walls.

Arundel Tower, Southampton

Arundel Tower, Southampton

Ideally a castle would have enough towers around its curtain wall to allow archers and crossbowmen to cover all of the ground outside and inside.

Archers and crossbowmen were not the towers only means of defence. Mangonels and other forms of catapult could be used from the tops of towers. This would give them a greater throwing distance than similarly sized catapults used by the besiegers.

This last tower is from a bishop’s palace. Despite its name, Wolvesey Castle isn’t a castle, although it was fortified. It was built by Henry of Blois, Bishop of Winchester, in the mid-twelfth century. He was the brother of King Stephen, whose reign was mostly taken up with the civil war known as the Anarchy.  Somewhat surprisingly, given that he was the king’s brother, Henry changed sides more than once, necessitating the fortification of his palace in Winchester.

Wymond's Tower, Wolvesey Castle, Winchester

Wymond’s Tower, Wolvesey Castle, Winchester


April Munday is the author of the Soldiers of Fortune and Regency Spies series of novels, as well as standalone novels set in the fourteenth century.

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Filed under Castle, Fourteenth Century, Medieval Buildings

13 responses to “The Anatomy of a Castle – The Tower

  1. I left a comment, but the system would not let me send. Maybe this will go through. Also had to sign in three times. Thought things were getting better, but I’m back to not being able to “like”.

    If this gets through, I enjoyed this info & wondered if the Jack Falstaff types were at a disadvantage in those narrow embrasures? Also wanted to know if there’s any good info on the English fletchers’ craft? Know about English yew bows (of fame!), but what’s a bow without arrows?

    As always, wonderful! Thank you!

    Liked by 1 person

  2. On a TV doco I saw recently there was a demonstration of archers in a castle shooting through an arrow loop (using longbows). They had to stand quite a way back from the loop itself because the arrow has a wriggly/snakey motion when it first leaves the bow, and needs to be in straight flight to pass cleanly through the narrow external opening.

    There was a slow-mo shot, and the arrow looked as if it couldn’t make up its mind quite which direction to head in.

    I assume crossbowmen could stand nearer or possibly in the loop because the shorter, thicker bolt would be more rigid, and therefore less “snakey”.

    Liked by 3 people

    • I didn’t know that about arrows. That would make arrow loops a bit less useful. It’s something else to follow up in the library.

      Liked by 1 person

      • I saw it in the Mike Loades doco, “Going Medieval”. I think it’s the tail end of the arrow striking the bow as it goes through that causes the wobble.

        The other thing I saw was Mike Loades and another bowman taking turns to fire through the arrow loop. They were standing side-by-side in the tower and side-stepping into the shooting spot, thereby maintaining rapid fire. Impressive, but whether or not this was a much-used technique…

        “Going Medieval” is worth watching, though the enthusiastic presentation style took a bit of getting used to. For me, anyway. It was made in the UK for a US audience, but I’m a laconic Kiwi. I’m glad a I persisted.

        Liked by 2 people

  3. Thanks for the detailed explanations. I love learning about things like this.

    Liked by 2 people

  4. If I lived in a castle I think I would perpetually be holed up in the top of the tower. As a choice, not a punishment. Your posts are always so informative. Thanks for sharing.

    Liked by 1 person

  5. Pingback: Anatomy of a Castle | A Writer's Perspective

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