You learn something new every day.
It’s common enough in histories of Medieval philosophy to read about the lack of most of Aristotle’s corpus in the West until the beginning of the 13th century, and particularly that the Latin West received the rest of Aristotle from the Arabs. Josef Pieper’s Scholasticism (pp. 103-104), however, is the first book I’ve read in which an explanation is given for how the Arabs got Aristotle in the first place while the West lost him.
According to Pieper, the Arabs got Aristotle – believe it or not – through the Nestorians. We all know that Nestorius was an adherent of the Christological school of Antioch, but I, at least, did not realize that Nestorius was a Persian by birth. We all also know that the Antiochene Christological school stressed the human and historical “this worldly” aspect of Christ, but I, at least, did not know that this stress made Nestorians and Aristotelians (“this worldly” philosophers) natural allies against the more spiritual outlook of the Alexandrians and Platonists which came to dominate Western theology.
For a time both Nestorians and Aristotelians congregated in Edessa, Syria, but when Nestorianism was condemned by the Council of Ephesis in 431, both Nestorians and Aristotelians migrated from Edessa to Nisibis, Persia. There monasteries and schools sprang up in which the philosophy of Aristotle and the works of Euclid, Hippocrates, Galen, and Archimedes were preserved while they were being quickly forgotten in the West. Translated from Greek into Syrian, then from Syrian to Persian, these works naturally fell into Arab hands when Islam overran the Persian Sassanid kingdom in the seventh century.
So the Arabs got Aristotle from Western heretics. Ironic, then, how great a role Aristotle was to play (and still plays) in the defense of Western orthodoxy.