Al-Qastal considered one of the most famous Umayyad ruins, is located 25 km south Amman. The complex was established since the 8th century by Caliph Yazid bin Abd al-Malik. The most significant part in this site is the Umayyad Mosque and its unique minaret, which is presumed to be the oldest Islamic minaret in the Islamic world. The rectangular mosque is oriented off-axis from Mecca and facing Petra. Its original rectangular mihrab (prayer niche) was later replaced by a more typical semi-circular one, and its circular minaret is one of the earliest surviving minarets from the first days of the realm of Islam. A shaped cornice supports Corinthian pilasters.
The Mosque is part of a whole settlement composed of a main residential palace, a cemetery, a bathhouse, domestic dwellings, a substantial agricultural dam, a main reservoir and dozens of smaller cisterns. Similar to other Umayyad buildings, the decorations are a merge of Roman and Sasanian influences.
The fact that the Qasr al-Qastal complex was finished while the nearby Qasr Mshatta was never completed indicates that Qasr al-Qastal may be the oldest Umayyad construction in the area. Tombstones from Al-Qastal indicate that after the fall of the Umayyads, the site was used by the Abbasid Caliphate.
