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Why Were Castles and Fortresses Important During the Middle Ages?

Throughout the years, I have seen God knows only how many movies and tv shows which are set in the Medieval and Early Modern period, either depicting real-life events or fantasy worlds. These shows try to depict a sort of realistic world that one could almost mistake for the real era which they depict.

Castles are often seen as the symbols of the Medieval period, and one of the recurring statements I had a hard time understanding a few years ago always sounded like this:” There’s not much ahead of us but there is this castle, the castle controls the whole area, we must take it before we move further”, and then the camera shows the castle.

It was sometimes an impressive structure, more often not at all, and I am like, how the hell can that pile of rubble manned by like 200 men control any area? The writers of the movies never really explained the statement and I was like, whatever if you say so.

Last few years I more or less quit watching movies like this( generally standalone movies of about 90 minutes, no real meaning, no real depth, just people hacking each other to pieces), and I rather spend my time reading. Luckily for me, I bumped into some good books about Medieval and Early Modern military history that finally cleared my confusion.

Castles allowed Feudal Grandees to defy their monarchs

First of all, the state as we know it today did not exist in the Medieval era and only started to be born in the Early Modern period. In the modern world states and their representatives control their organs which are state-sanctioned to use brute force if necessary (military, police force), issues currency and laws. In Medieval Europe, for example, the world was a very different place, and state control usually stretched over only the lands of the monarch, while powerful nobles and churchman had their private military forces and feudal and church jurisdiction of the lords coexisted with the royal.

As the great lords had their private militaries just like the king, they also built castles with which they controlled their lands. These castles were built in carefully selected positions, usually on elevated ground, along the major rivers or roads that crossed the land.

The castle was often where the people from the countryside that surrounded the castle retreated to. The main economical asset of the period was land, but barren land was as good as useless, so lords let peasants( free or unfree) work their lands in exchange for a percentage of what the peasants produced. If there was no place where the peasant could retreat in case of an attack and were all killed, captured or enslaved, then the lords were in deep trouble, as they remained without their workforce.

Thanks to the good defensive positions and strong walls, these strong points were often very hard and very costly to capture by siege. A defender force of a few hundred men was potentially able to withstand a significantly larger attacker force for quite a while. If the defences of the castle were too strong, the attacker usually chose to surround and starve it out, but this was often costly for the attacker too. The castles were usually well supplied with food and had provisions for months. The attacking force ,on the other hand, oftentimes had a hard time living off the land and feeding themselves, especially if it was a big army besieging the castle. Starvation and diseases broke out frequently during sieges and decimated the besieging armies.

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The Royal Families were oftentimes the strongest ones in most states, however, so long as the feudal grandees had numerous castles, and this was frequently the case( in Medieval Hungary, for example the most influential nobles often had 10-20, sometimes even 40 such strongpoints) they knew that they could confidently defy their monarch.


This balance of power started to change after the usage of artillery became widespread, and medieval castles ceased to be the safe hiding places which they used to be( provided that the attacker had a huge artillery train). Monarchs tried to monopolize the materials which were needed to produce gunpowder, thus, the relative equilibrium between monarchs and feudal grandees shifted in favour of the monarchs between the 15th and 17th centuries. The artillery proof modern fortresses were incredibly expansive to build and these also required bigger garrisons than the Medieval Castles.

As the nobles were turned into state servants, infighting between the king and nobles decreased. Unfortunately, this development did not mean that peace was restored to Europe, quite the contrary, instead of fighting the monarch or each other, the bellicose nobility waged war on behalf of their king against other states.

Probably the best example of this transformation was Louis XIV of France. During his childhood, the nobility was rebelling against him, by the end of his rule, he turned them into ministers, generals or diplomats of France.

Fortresses in the Age of Siege Warfare

Early Modern military history in Europe, especially in Western Europe, was dominated by siege warfare. Probably the best example of this was the Eighty Year’s War between Habsburg Spain and the Dutch Republic. Another good example was the Hungarian-Ottoman wars of the 15th and 16th centuries. In the following, I will use this latter example to demonstrate the importance of fortresses.

Between 1463 and 1521, the southern borders of Hungary were guarded by a chain of fortresses. These fortresses were spread too thinly to stop the rapidly moving Ottoman raiders, but the garrison troops were often able to intercept the raiders who were returning packed with loot. One good example of this would have been the Battle of Breadfield in 1479, when the Hungarians intercepted the retreating Ottomans and destroyed the large raiding party.

The fortresses were not capable of stopping the raiders, but thanks to their good strategic positions, most were built along the major rivers of the area like the Danube, the Sava or the Drava, any large invading army which wanted to use these rivers as a supply route needed to neutralise the strongpoints. Belgrade and Sabac were the most important ones, and Belgrade in that period was simply known as the gateway of Hungary.

The river route into Hungary of course was not the only one, but the land roads were often of very bad quality, so heavy rains were capable of turning these into seas of mud, which potentially could have slowed down or even blocked the supply lines of any large army, which could jeopardize the whole campaign. For this reason, controlling the rivers was very important, and it was no coincidence that the Ottomans conquered Hungary only after the border fortresses were captured and the Sultan was able to advance with his huge army into the heart of the kingdom, where he easily annihilated the ragtag Hungarian Royal Army at the Battle of Mohacs in 1526.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2022 Andrew Szekler

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