The Persian chronicler and geographer Ibn al-Faqih (10^th century) recounts that during works on the mosque, workers discovered an underground chapel containing the head of Saint John the Baptist. Told of the discovery, the Caliph al-Walid I is said to have ordered the burial of the holy relic in the prayer hall, under a pillar which was then faced with marble and since monumentalised by a domed aedicule. These relics are revered by Christians and Muslims.

Felix Bonfils, 1875.