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Building a castle

Building a square keepThe most important factors to be taken into consideration when building a castle were that it should be able both to resist attack and to withstand a siege for at least several months. It needed to have high, thick stone walls and be located in a good position. With only a few basic kinds of tool available, most of the work to build a castle was achieved by a combination of skilled craftsmanship and muscle power. Between 2000 and 3000 men, including masons, blacksmiths, carpenters and labourers, would be required if the job was to be completed within a few years.

A small army of workers building a castle.
A good site for a castle might be on a small hillock close to a river crossing, but away from an area likely to flood. The site...Read More >>A good site for a castle might be on a small hillock close to a river crossing, but away from an area likely to flood. The site (marked by red flags) would command this important route and so control the surrounding area. The river might also usefully be diverted by engineers to fill a moat. The village and cropfields are also close by, providing both local workers and food supplies for the castle.

Siting the castle

The first decision to be made was where to build the castle. Some castles were perched high on crags or mountains, but most were located on low ground. There were several reasons for this. It would be useful if the people from local villages could visit the castle easily: supplies and labour would then be easier to come by. Most importantly, the castle would be far better able to survive a siege if fresh water could be obtained from within the castle walls themselves. Wells could be dug down to the water table much more easily in a lowland location. It was also more difficult to dig tunnels in soft valley gravels, which would give the castle extra protection against undermining by a siege army. 

It was often difficult for water from a river or lake to be diverted around a castle to form a moat. Water-filled moats could also be foul-smelling as waste from kitchens and garderobes was frequently dumped in them. Many castles therefore had only a dry ditch surrounding their walls.

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