The castle was built by the Order of St. John, and held by them from 1142 until 1271. While the Knights Hospitaller had build the world's first concentric castle at Belvoir, Le Crac, in its adaption to the contours of the site is considered the finest example. Le Crac had survived with remarkable completeness, (at least until it was bombed by the Syrian air force in July and August 2013, the damage is unknown.) Crac es Chevaliers had been one of the few crusading castles to have been been excavated and restored using modern archaeological methods. The original fortress known as Qalaat al-Husn, or the Fortress of the Kurds was occupied briefly by the crusaders on their march south in 1099, but not occupied by them permanently until 1110, as a dependency of the county of Tripoli. But the county of Tripoli, without any of the great religious sites was struggling to recruit immigrants from Provence, the heartland of the crusaders, where the Cathar heretics, were already undermining support for the crusade.
To make up for his deficiency in manpower, in 1142 Count Raymond invited the Order of St John to take up the defence of his northern border. The Arab counter attack was threatening to drive through to the coast which would have cut his county in two and divided it from the Principality of Antioch to the north. So Raymond made over five castles to the Hospitallers, Mardabech, Lac, Felice, Chateau Boquee and Le Crac des Chevaliers itself, together with a vast frontier march in what amounted to an autonomous palatinate, the count bound himself not make make peace with the Arabs without the consent of the Hospital. He also made over to them Rafaniyah and Montferrand which were already in Muslim hands.
Crac des Chevaliers occupied a vital strategic position on an isolated summit, a spur of the Ansirayah Mountains, lying just to the north of the plain known to the crusaders as La Bocquee and to the Arabs as the Bekaa valley. The fortress commanded the whole area between the important Muslim towns of Hama and Homs and nearly intersected the route between Damascus and Aleppo. What think you of a town wrote Ibn-Jubair when he visited Homs, that it is only a few miles from Qalaat al-Husn, the stronghold of the enemy, where you can see their fires and whence each day the enemy may raid you on horseback. The plain was the main channel of communications between the coast and the Orontes valley to the east. The narrow entrance to the plain, the Homs gap became the scene of some of the most desperate fighting between the Franks and the Muslims. To the south of the plain cliff wall of the Akkar Mountains are the northern extremity of the Mount Lebanon massif and the Hospitallers also held a small castle there. .
It is unclear how much of the Arab castle had been rebuilt by the time Le Crac was handed over to the Hospitallers in 1142. But it seems that the inner enceinte was built by the Order soon after they occupied the castle. In plan it is an irregular polygon the shape, dictated by following closely the contours at the end of the steep promontory. The curtain walls are rounded on the north side but have an obtuse angle on the south side, they are strengthened by square towers and enclose the courtyard.
The second half of the twelfth century was a period of high seismic activity in the region, and considerable damage to the fabric of Le Crac was reported after an earthquake in 1170. But as Saladin left Le Crac unchallenged during his march north in 1188, the walls must have been rebuilt by then.
Around the turn of the thirteenth century the outer enceinte was added to provide a second concentric line of defence. The new outer line of defence was protected by 12 projecting semi-circular towers. Inside, these towers had rectangular halls at ground level, each provided with three loop holes, one in the center, and one each at the junction of the tower and wall, commanding the base of the wall on either side. The walls of the new enceinte also considerably enlarged the scale of accommodation within the fortress, providing more space to afford protection to the villagers and their livestock from the surrounding estates.
Once the outer enceinte was added it was possible to undertake considerable rebuilding of the original castle. The central tower of the west wall was converted to a semi-circular tower by being embedded in the massive walls. A huge talus was piled up against the curtain wall on the west and south sides making it virtually indestructible.
A small inscription (in Latin) is carved in the loggia.Sit tibi copia, sit sapienta, formaque detur,
Inquinat omnia sola superbia si comitetur.
'Yours may all wisdom, wealth and beauty be. But pride the arch corrupter flee.'
Behind the great hall is a long windowless and almost underground hall thought to have been the living quarters, latrines and communal dining room for for the soldiers and non-combatants. At one end is the bakery, the flour ground by the windmill that had been on top of the tower above.
On several occasions the Muslims attempted to reduce Le Crac. Nur ed-Din, lord of Aleppo and Edessa, encouraged by the failure of the Second Crusade had already tried to take it. He had destroyed the armies of Raymond, Prince of Antioch and of Joscelin of Edessa when he set up camp beneath the walls of Le Crac in 1163. The garrison was reduced to a token force and in an act of desperation they rode out and charged the Sultan's camp which was scattered, and pursued all the way to the lake of Homs. The battle of La Bocquee as it was called was one of the greatest feat of arms of the Hospitaller's at Le Crac.
In the aftermath of his great victory at Hattin in 1187, when he annihilated the crusaders' army, Saladin took one crusader fortress after another, until the strength of Le Crac's defences deterred him from even making an attack.
Le Crac proved to be impregnable, until April 1271. In February of that year Sultan Baibars had determined to drive the crusaders out of the Holy Land and his set up camp outside the mighty fortress. On the last day of March his forces undermined the tower in the south west corner and fought their way into the outer ward, massacring the Hospitallers, taking prisoner their serants, but letting the villagers go free, to maintain cultivation.
Baibars may well have been daunted when faced with the awesome prospect of the southern talus. According to some accounts the Sultan sent the remaining Hospitallers holding out inside the inner enceinte a forged letter from Tripoli, ordering them to surrender.. On 8th April, with the certain knowledge that no reinforcements were going to come to their rescue, the Hospitaller garrison received a safe conduct and rode out of their most famous castle for the last time.