Prosper of Aquitaine

Prosper was born about 390 in Aquitaine, in southwestern Gaul, and seems to have been driven out by the barbarian invasions of the region. He was a layman, well educated, a poet, never ordained as far as the record shows, and he settled at Marseilles.

Marseilles was the wrong city for a follower of Augustine. It was the home of John Cassian's monasteries, and the monks there had serious objections to what Augustine had written on grace and predestination in his old age. They agreed that grace was necessary; they would not agree that the very first movement of the will toward God comes from grace alone, and they thought that unconditional predestination made preaching and effort pointless.

About 428 Prosper and a friend named Hilary wrote to Augustine in Africa to tell him what was being said. Augustine answered with two of his last books, On the Predestination of the Saints and On the Gift of Perseverance. Then, in 430, he died, and Prosper spent the next twenty-five years defending him.

He did it in every form he could. He wrote a long poem, On the Ungrateful, meaning those without grace, running to a thousand hexameter lines. He wrote epigrams drawn from Augustine's sentences. He answered the objections of the Gauls and the Genoese point by point. He wrote Against the Collator, a direct attack on Cassian's thirteenth Conference. Around 431 he went to Rome to get papal backing and obtained a letter from Celestine commending Augustine's memory, though it settled nothing.

Over the years his own position softened. In the Call of All Nations, generally reckoned his, he presses hard on God's universal saving will, that God genuinely wills all men to be saved, and works to hold that together with the doctrine of grace. Later Latin theology mostly followed Prosper's version of Augustine rather than the sharpest form of Augustine himself, and the Second Council of Orange in 529 settled the matter along broadly these lines.

One sentence of his outlived all the arguments. Writing about how to settle a doctrinal question, Prosper said that the rule of prayer establishes the rule of belief, ut legem credendi lex statuat supplicandi. His point was concrete: the church has always prayed for the conversion of unbelievers, therefore the church has always believed that conversion is God's gift. The line has been shortened ever since to lex orandi, lex credendi, and it is quoted in every serious discussion of worship and doctrine.

In his last years he was at Rome, apparently as a secretary to Pope Leo the Great, and some scholars think he had a hand in drafting Leo's letters. He also kept a chronicle continuing Jerome's, which is a first-rate source for the 430s and 440s in the West, including Leo's meeting with Attila. He died after 455.

Sources: Prosper of Aquitaine, De vocatione omnium gentium, Contra Collatorem, and the Epitoma Chronicon (English translation of the doctrinal works in Ancient Christian Writers 14 and 32); Augustine, On the Predestination of the Saints; Philip Schaff, History of the Christian Church.