Ambrosiaster

Ambrosiaster is a nickname for a man whose name was lost. It was coined by Erasmus in the sixteenth century, and it means roughly "the pseudo-Ambrose" — because for a thousand years the church read this author's commentary on Paul believing it was the work of Ambrose of Milan. It is not. What can be said with confidence comes from the text itself. He wrote at Rome. He wrote during the pontificate of Damasus, which fixes him between 366 and 384. He used the Old Latin Bible, not Jerome's new Vulgate, which is one reason his commentary matters: it preserves the Latin text of Paul as it stood before Jerome revised it. He knew Roman law and Roman civic life well, and he wrote for readers who did too. His achievement is the first complete Latin commentary on the thirteen letters of Paul. It is not allegorical and not showy. He explains what the apostle is saying, sentence by sentence, in ordinary Latin, with attention to the historical situation of each church Paul was writing to. Where a passage is hard, he says so and gives his best reading. Augustine used him. Pelagius used him. The medieval schools used him constantly, believing all the while that they were reading Ambrose. A second large work, the Questions on the Old and New Testament, is generally credited to the same hand. It travelled under Augustine's name, which is the same accident happening twice. His reading of Romans 5:12 became one of the most consequential sentences in Western theology. The Old Latin rendered Paul's Greek as "in whom all sinned," referring the phrase to Adam, and Ambrosiaster read it that way. Augustine took the reading from him and built on it, and the doctrine of original sin in the West carries the mark of a Latin translation that an anonymous Roman commentator explained without fuss. Guesses at his identity have included Isaac the converted Jew, the Roman official Decimius Hilarianus Hilarius, and others. None has held. What is left is the work: clear, sober, unmistakably the product of a trained mind, and completely anonymous. Sources: Ambrosiaster, Commentaries on the Pauline Epistles (Corpus Scriptorum Ecclesiasticorum Latinorum 81); Alexander Souter, A Study of Ambrosiaster (1905); The Catholic Encyclopedia (1913), s.v. "Ambrosiaster".