Krak des Chevaliers is a Crusader castle in Syria and one of the most important preserved medieval castles in the world. It is located approximately 40 kilometres west of the city of Homs, close to the border of Lebanon.
In 1142 it was given by Raymond II, Count of Tripoli, to the Knights Hospitaller. It remained in their possession until it fell in 1271. It became known as Crac de l'Ospital; the name Krak des Chevaliers was coined in the 19th century.
The order controlled a number of castles along the border of the County of Tripoli, a state founded after the First Crusade.
At its peak, Krak des Chevaliers housed a garrison of around 2,000.
From the 1250s the fortunes of the Knights Hospitaller took a turn for the worse and in 1271 Krak des Chevaliers was captured by the Mamluk Sultan Baibars after a siege lasting 36 days, and then purportedly only by way of a forged letter claiming to be from the Hospitallers' Grand Master that caused the Knights to surrender.
Renewed interest in Crusader castles in the 19th century led to the investigation of Krak des Chevaliers, and architectural plans were drawn up. In 1933 the castle was given over to the French state, under which a programme of clearing and restoration was carried out. When Syria declared independence in 1946, the castle left French control. Since 2006, the castles of Krak des Chevaliers and Qal'at Salah El-Din have been recognised by UNESCO as a World Heritage Site.