Brief accounts of Sargis'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).
We have mentioned earlier how this man assisted when al-Mutawakkil passed through Damascus and established an excellent relationship with him.
After the death of Theodosius the caliph ordered that he should be appointed patriarch, but was warned that the metropolitans of Nisibis were not allowed to become patriarch because Bar Sawma had contrived the murder of Babowai and Yohannan the Leper had tried to murder Mar Hnanishoʿ.
The caliph ignored this custom, and Sargis was consecrated in al-Madaïn on the Sunday after the fast of the apostles, on the twenty-first day of tammuz [July] in the year 1171 of the era of Alexander [AD 860].
Instead of going to Dorqoni he went to Baghdad, where he was received with great honour, and from there went on to Samarra, where he could deal with matters needing his attention.