It wasn't just the Byzantines who had a thing for frescoes, you know. The Umayyad rulers (the first of the Arab empires) had a bit of a fancy for artistic frippery as well. Jordan's so-called "desert castles" amid the stark sand plains east of Amman are proof of that, and Qasr Amra is the best example.
The term "castle" is something of a misnomer. Qasr Amra (and the other "castles" of Kharana, Azraq, and al-Hallabat, which can all be seen on a day trip from Amman) were more part posh hunting lodge, part caravanserai—where Umayyad rulers escaped to when the strains of city living in Damascus got too much.
The 8th-century Umayyad caliph Walid I (whose reign also saw the construction of Jerusalem's Dome of the Rock and Damascus' Umayyad Mosque) built Qasr Amra and had the walls and ceilings here decorated with exuberant and surprisingly bawdy frescoes. The risqué content depicted will change your perception of art in the early days of Islam.