In both the County of Tripoli and the Principality of Antioch, there are Crusader castles whose ruins clearly show that they were built in the twelfth century, although the evidence for dating them is less full than in the Kingdom of Jerusalem. The great tradition of narrative history which begins with Fulcher of Chartres and is carried on by William of Tyre and his continuators is firmly based in the Kingdom of Jerusalem; it does of course deal with major events in the north but has little to say about less dramatic matters like the foundation of castles.

A different landscape also produced different styles of castle building. Apart from the area around the city of Tripoli itself, the northern Crusader states had fewer areas of flat fertile land than the Kingdom of Jerusalem. Chronicles mention Crusader castles built, mostly in the first half of the twelfth century, in the rolling hills and steppe lands beyond the Orontes river but none of these has left enough remains for us to form a clear idea of their plans. Few pilgrims visited this part of the Crusader lands so there was less need for castles to protect the roads. As a result, neither isolated donjons nor rectangular enclosure plans were widely used in the northern states, except in the fertile and well-settled areas of the County of Tripoli. On the other hand the rugged limestone hills of the area lent themselves ideally to the construction of ridge castles. This development was aided because, unlike the Kingdom of Jerusalem, this was already a land of castles.