Middle Eastern Impact on Medieval European Castles

When European Crusaders began returning from the Middle East in the 11th century, they brought with them a variety of defensive innovations that they had witnessed. One of the most important was the idea of a concentric castle. This was really just an extra wall ringing the existing castle wall, but this addition could have a major impact in the outcome of a siege. Any attackers who were able to break through the outer defensive wall would come up against a second ring of walls, higher than the first, and would be trapped in the space between. This allowed defenders to pick off the trapped assailants from relative protection on either side.

Typical early Norman castle designs featured a square keep, with 4 vulnerable corners. If attackers could pry out a cornerstone, they could collapse the wall and breach the keep. But in the Middle East, commanders noticed that the round fortresses they encountered were much more difficult to 'sap', due to their shape and lack of corners. Soon rounded keeps became standard practice in European countries as well.

A third innovation brought back was the barbican, or extra gatehouse placed in the middle of the moat in front of the main gate. Like the addition of an extra ring of walls, the idea itself was less of a new concept than just better use of an old one. While castles all featured a gatehouse around the gate itself, a barbican placed in front made it more than twice as difficult to breach, as attackers would have to breach this defense before they could even reach the main gate. The barbican was a castle in miniature, with its own portcullises on either side and murder holes strategically placed in the ceiling of the passage, from which rocks arrows and boiling oil could be dispensed.