[1] Brief accounts of Gregory'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).
A lengthier and more circumstantial account is given in the Chronicle of Seert, an anonymous ninth-century Nestorian history.
The following account of Gregory's patriarchate is given by Bar Hebraeus: In the year 915 [AD 604], after hearing that his father-in-law Maurice had been killed by the Greeks, Khusro Abroes broke the peace, and setting out against Dara besieged it for nine months and captured it.
He had a number of disciples of poor repute, on account of whom he was held in contempt not only by his own people but also by the Persian nobles.
Then the Persians put his disciples to the question until they handed back all the money that had been amassed by their master.