 His consecration as patriarch was soon followed by the fall of Roman Syria and the Muslim conquest of the Levant.On 9 May 644, John and several bishops were summoned before Emir Umayr ibn Sad al-Ansari of Hims to engage in open debate regarding Christianity and represent the entire Christian community, including non-Syriac Orthodox communities, such as Greek Orthodox Syrians, who are known to have prayed for their safety.The debate was recorded by a certain Severus in the form of a letter and sent to Syriac Orthodox communities to ease discomfort amongst the adherents of the church.