Aaron Riches’s book Ecce Homo brought to my attention fascinating connections between soteriology and Christology in the fourth and fifth centuries. I’m not really surprised that the Christological debates of this period were connected with the Western controversy over Pelagian “works righteousness,” a major concern of the Regensburg Forum (here, here, etc.). Besides the integrated character of Christian theology itself, thinkers like Augustine and Cyril of Alexandria knew better than most of us that all of these doctrines were interconnected. And of course the doctrines about grace and our salvation have their source in the work of Christ.

Nestorianism was condemned as an excessively dualistic account of the natures of Christ. Of course, Chalcedonian orthodoxy (451) clearly affirmed that “one and the same Christ Son, Lord, only-begotten” is “acknowledged in two natures without confusion” and “without change” but also “without division” and “without separation.” The concern was the Nestorian tendency to division and separation. But what does Nestorianism have to do with Pelagianism?

Nestorianism was condemned at the Council of Ephesus (431), just a year after the death of Augustine of Hippo, the great opponent of the Pelagian heresy. Nestorius’s great opponent, Cyril of Alexandria (d. 444), received a letter from Augustine some time between 417 and 421. According to Riches, (48), this letter shows that Cyril sent Augustine the Acta of the 415 Synod of Diospolis which “vindicated Pelagius.” “This gesture,” he says, “suggests some common cause between the great Latin doctor and the Alexandrian pope, especially in light of the condemnation of Pelagianism at Ephesus, which effectively reversed the ruling of Diospolis.” It is likely that Augustine sent more materials about Pelagianism to Cyril along with this letter (De gestis Pelagii).

The condemnation of Pelagianism at the same council that is so famous for condemning Nestorianism might indicate a deep connection. But most scholars have seen Cyril’s effort to condemn Pelagianism “as a way of paying Pope Celestine back for his support in condemning Nestorianism.” It has basically been seen as a courtesy of the East towards what the Greeks deemed to be a Western spat.

Riches argues that this was not the case, drawing upon the work of John Cassian, “the foremost expert on Greek affairs” (45). Now, Cassian has been accused of Semipelagianism for a long time in the West, but this charge has apparently been addressed rather effectively in the work of Augustine Casiday. At any rate, Cassian wrote the following in his work On the Incarnation of the Lord against Nestorius:

If Christ who was born of Mary is not the same one who … was born of God [referring to the controversy over Nestorius’s denial that Mary is Theotokos or God-bearer], you undoubtedly make two christs, according to the impious Pelagian error, which by asserting that a mere man was born of the virgin, said that he was the teacher of the human race rather than the redeemer, for he came to bring to people not redemption of life but [only] an example of how to live.

Cassian saw Nestorianism as implying that the Savior was “born a mere man”; similarly, Pelagianism makes it so that “our Lord Jesus Christ lived as a mere man entirely without sin.” Without a strong account of union between the Second Person of the Trinity and the humanity of Jesus (Nestorianism), it is no longer clear how it is God Himself who saves us from our sins on the Cross. In that event, Christ turns into a moral example of what God demands of us (Pelagianism). As Riches puts it, “The centrality of the Cross, then, as the event of divine salvation apart from which the human being cannot truly find himself, is precisely what eludes the logic of both Pelagianism and Nestorianism and is internal to their convertibility. Hence the truth of the famous dictum: ‘The Nestorian Christ is a fitting savior of the Pelgian man.'”

The historical and conceptual connections between Nestorianism and Pelagianism (only sketched here, of course) might also help to clarify what is actually at stake in Augustine’s anti-Pelagianism. Instead of thinking of Augustine as simply opposing Pelagius’s works righteousness or Pharisaism–the fact that he opens the door to human pride and self-righteousness–perhaps there is something deeper at work. Here is Riches’s account (49):

Nestorian Christology exhibits what Georges Florovsky called an “anthropological maximalism.” Hence Nestorius’s thought has been recognized as conducive to the anthropocentric agendas of modern “human-centered” Christologies “from below.” But the apparent “anthropological maximalism” of Nestorius here organically deflates into an “anthropological minimalism,” since by presuming to apprehend all that “fully human” might mean in abstraction from the Incarnation it effectively limits the horizon of authentic humanity. A true Christian “anthropological maximalism,” by contrast, must rest in the expansive horizon of Jesus Christ as the content of true humanity.

Augustine’s attack on Pelagianism was not that Pelagius wanted too much from human beings but ultimately that he wanted too little. Christ did not come “down from heaven” (Nicene Creed) to make us into Stoic sages. For Augustine, he came to incorporate us into his life so that we might partake of the divine nature (II Pet. 1:4). This account requires not only a rich account of divine grace but also the high Christology articulated by Cyril of Alexandria and set forth by the ecumenical councils.