They are known from pre-Islamic Syria, where the form was used in the fourth century CE in the Baptistery of Mar Ya'qub (St. Jacob) at Nisibin[1] and Qasr Ibn Wardan (564 CE).[2] Some argue that it was used earlier in the Sassanian Taq-Kasra in Iraq.[3] It was adopted immediately by the Islamic caliphates, with a form of it appearing in the Mosque of Amr ibn al-As in Cairo,[3] the Great Mosque of Damascus[4] (706-715 CE), Qasr al-Hayr al-Gharbi (727 CE), it appears in friezes in the ruins of Qasr al-Qastal and it is extremely prominent throughout the Umayyad palace at Amman Citadel in Jordan.