Today (August 29) the Holy Syriac Orthodox
Church (ܥܕܬܐ ܣܘܪܝܝܬܐ ܬܪܝܨܬ ܫܘܒܚܐ, ʿīto suryoyto trīṣaṯ šubḥo) commemorates the beheading of the Forerunner St. John the Baptist (Mor Yohanan Mam'dono). His mortal remains are entombed in the Basilica of Saint John the Baptist in Damascus Syria.
After the rise of the Umayyad Dynasty, this church was converted into a mosque. However, the shrine housing his remains was kept intact. Today, Umayyad Mosque or Great Mosque of Damascus (Ğām' Banī 'Umayya al-Kabīr) continues to be a pilgrim site for both Christians and Muslims (to whom he is known as prophet Yaha)
Photo of the Basilica @