The speed of the collapse of the Crusader-held enclaves along the eastern Mediterranean coast came as a shock to Catholic Christian Europe. This was all the more painful because so much effort and expense had been put into their fortifications. Yet despite the impressive nature of some castles and urban defences, their subsequent fate depended upon their location rather than their strength. In general, those on the coast were demolished and abandoned by the Mamluks whereas many of those sited inland, especially overlooking strategically important passes, continued to be used. In many cases the latter were then considerably strengthened.
Despite several exceptions, the one feature that seems to have been consistent in Mamluk strategy was that the Muslim conquerors demolished those places they felt unable to garrison adequately, and which could become the targets of Crusader counter-attacks. If a castle was more vulnerable than useful, it was destroyed. On the other hand, the new Mamluk rulers seem to have tried to maintain existing western European forms of land tenure and peasant servitude, which had proved very effective in supporting the Crusader military elite. Unfortunately - from the Mamluks' point of view - this was not practical, as under Islamic law it was illegal to enslave fellow Muslims, even the poorest peasants, or tie them to land as serfs.
The fate of Jerusalem, as an important (though small) inland city, was less clear cut. Most Crusader fortifications here were broken down though not entirely demolished, with the exception of the Tower of David citadel. Here the lower parts of the Crusader structure remained largely intact, including the glacis, while the main tower above was rebuilt as the Mamluk garrison's only strong fortification within the city. The 12th-century fortresses in what is now southern Jordan had already been strengthened by the Ayyubids (see Fortress 21: Crusader Castles in the Holy Land 1097-1192), and this process continued under the Mamluk rulers from the mid 13th to the end of the 15th century. A comparable process was seen in the coastal mountains of Syria where archaeologists have found that more of the famous 'Crusader castle' of Crac des Chevaliers is actually of Mamluk construction. The same has been found at Belfort in southern Lebanon.
The Burj al-Hazna or Treasury Tower stands next to the northeastern corner of the Hospitaller fortified convent in Acre. Its foundations are on one of the biggest towers of what had been the northern wall of the city. Beyond this the new suburb of Montmussard was fortified during the 13th century. The Hospitaller Convent, also known as the Citadel, is behind the high wall on the left.
When archaeologists found this remarkable stone-lined tunnel beneath the old city of Acre, it was filled with rubble to within less than a metre of the roof. Once cleared, however, it proved to be a large structure linking the centre of the city with the area of what had been the Templar castle in the south-western corner of Acre. Though not ‘secret' in any real sense of the word, the tunnel was probably private.
Down on the coast of Palestine, the citadel of Arsuf was rased by the Mamluks after its capture in 1265, never to be used again except for a brief period during the First World War when British troops established a strongpoint in its ruins. After Tripoli fell to the Mamluks, its new rulers largely abandoned the Crusader coastal city, which declined into the small fishing port of al-Mina. Only later did the Mamluks build some coastal towers to guard the port. Meanwhile, a new Islamic town developed around the Crusader Castle of St. Giles, as it was widely known, which was on a steep hill a few kilometres inland. This became modern Tripoli.
There is a joke amongst scholars specialising in medieval Middle Eastern fortifications that the great Mamluk Sultan Baybars was 'a great builder of Crusader castles'. A similarity in military building techniques on both sides of the Crusader-Saracen frontier still causes problems when it comes to identifying who exactly built what. There was certainly a flow of technical and stylistic ideas in both directions, but it is often difficult to state who were the instigators of new ideas or the most original developments. What is clear is that during the Crusader period the Middle East served as an important centre for the dissemination of developments within the art of fortification, and did so in all directions. Those directly responsible for transmitting such ideas could range from humble Italian sailors to the Grand Masters of the Military Orders. Amongst the latter, Hermann von Salza, Grand Master of the Teutonic Knights, is credited with bringing new concepts of castle design from the Middle East to the rather backward province of Thuringia in Germany. He is unlikely to have been alone.