[3] His life is described in the Syriac Chronicle of Bar Hebraeus (1226–1286): Theophilus served the Caliph al-Mahdî, who esteemed him very much because of his superiority in the art of astrology.
Theophilus replied to the servant who had brought him this message: "Return to your mistress and say to her: "It is not I who have advised the king to take this trip; he travels when it pleases him to do so.
When the Queen had heard these words, she was seized with a great fear, and she wondered apprehensively what the result would be.
Theophilus wrote the following works on astrology in Greek: These books have been preserved more or less intact, along with fragments of their Arabic versions.
The Jacobite patriarch Dionysius of Tel Mahre (818–45) cited it on several occasions in his own world history, the Annals.