From the 7th century Jordan flourished under the caliphs: the Umayyads built the desert palaces of Quseir Amra, Qasr al-Hallabat and Qasr Mshatta. Crusaders then raised the great fortresses of Kerak and Shobak, eventually retaken by Saladin's Ayyubids and held through the Mamluk and Ottoman eras.
These centuries left the castles and caravanserais that still define much of the landscape.