Brief accounts of Yohannan's patriarchate are given in the Ecclesiastical Chronicle of the Jacobite writer Bar Hebraeus (floruit 1280) and in the ecclesiastical histories of the Nestorian writers Mari (twelfth-century), ʿAmr (fourteenth-century) and Sliba (fourteenth-century) The following anecdotes of Yohannan's patriarchate are given by Bar Hebraeus: At the same time the catholicus Enosh, having fulfilled his office, died at the beginning of hziran [June] in the year 270 of the Arabs [AD 883].
After they had fasted and prayed, the name of Yohannan bar Narsaï was drawn, and he was consecrated at Seleucia in the year 271 of the Arabs [AD 884].
Seven months after his consecration the accursed Arabs pillaged the monastery of Klilishoʿ, and after burning and destroying its roof they broke open the burial place of the catholicus Enosh in the patriarchal cell, cut off his head, stuck it on the point of a lance and paraded it around the streets.
After Bar Narsaï was appointed, he came as usual to ask for his tip, but the patriarch said, 'Do not continue to indulge him in this thing, lest he becomes grasping and gives us no peace.'
They then went away and buried the dead man, but later came back and did those dreadful deeds in the monastery and the cell.