I'm reading Lawrence in Arabia right now and the author spends time talking about Lawrence's trek through the middle east (or I suppose technically the near-east?) looking at crusade-era castles to try and determine which way advancements in fortification technology migrated (I assume he went west to east, and at one of those ends he expected to find the most primitive fortifications?). The book talks about how Lawrence published it as his thesis at Yale Oxford and it received a lot of acclaim among academics for its original work, but never actually talks about what his conclusion was.
Does anyone know what Lawrence's conclusion about the migration of technology during the crusades was, and if it still holds up today?
Edit: Completely mixed up Yale and Oxford in my head
Almost entirely the other way around. In the first crusade, there are numerous account of Europeans marveling at the fortifications of Byzantium, Anatolia, and the Levant. At this time in Europe, castles consisted of little more than a primitive motte-and-bailey design, nearly always palisades, although there were some stone fortifications. These all pale in comparison to the massive walls of cities like Nicaea and Antioch, which they would encounter on their journey.
You may be wondering how the managed to gain the equipment and knowledge to defeat such structures - this came almost entirely through the Byzantines, who, through their accompanying legate Tatikios, advised the western Europeans on dealing with the principles of laying siege to such enormous structures.
It's also interesting to note that not only did these massive fortifications enter Europe through the middle east and Byzantium, but so too did their means of destruction - siege engines underwent an enormous development during the crusades.