evidence: Qasr al-Hayr al-Sharqi or "the Eastern Castle", (the Arabic term Qasr means a fortified structure for monitoring a region), is situated 97km North-East of Palmyra in the middle of the Syrian desert. It was built by the Umayyad Caliph Hisham ibn Abd al-Malik between 728 and 729 on a site chosen for its rich desert wildlife and was used as a military palace but also as hunting post and probably as a trade place. After the decline of the regional authority, the place was taken by the Abbasid caliph under Harun al-Rashid who used the palace until the fourteenth century. [...] Qasr al-Hayr al-Sharqi was excavated in six seasons between 1964 and 1971 by an American team led by Oleg Grabar. Since then, a Syrian team has conducted excavation and restoration work. Most of the decorations of the façade have been relocated to the National Museum of Damascus. [...] Qasr al-Hayr, Syria: 1964, 1966, 1969-71 "Économie de production, affirmation du pouvoir et dolce vita : aspects de la politique de l’eau sous les Omeyyades au Bilad al-Sham", by Denis Genequand, in: "Stratégies d’acquisition de l’eau et société au Moyen-Orient depuis l’Antiquité" by Mohamed Al-Dbiyat, Michel Mouton