ABSTRACT
Leo’s letters and sermons denouncing Manichees, Nestorians, Pelagians and Priscillianists reflect some of the many diverse Christian beliefs and practices that were current during his time. Leo’s bestknown intervention against a new ‘heresy’ (the criteria for which identification are discussed below) was his involvement in the Eutychian controversy, which was debated at the Council of Constantinople (448), the so-called ‘Robber Council’ at Ephesus (449) and the Ecumenical Council of Chalcedon. This christological controversy occasioned his famous Tome to Flavian, bishop of Constantinople, which became the touchstone of Chalcedonian orthodoxy. The most important elements of Leo’s christology as outlined in the Tome will be presented in the introduction to Letter 28, below. A brief treatment of Leo’s soteriology is included here to broaden our understanding of his theology as positive and constructive rather than simply ‘reactive’.1
As the late Basil Studer astutely observed, Leo’s christological doctrine is too often examined in isolation rather than as part of an overarching soteriology (Studer 1986: 765). The importance of this observation has been reinforced by two studies of Leo’s understanding of the economy of salvation, those of Armitage (2005) and Green (2008). Armitage focused his discussion on the concept of ‘twofold solidarity’, that is, Christ’s sharing of the same substance as Mary, his human mother, and God, his divine father. This idea was summed up in the Nicene Creed by the attribution to Christ of the adjective ‘consubstantial’ (Greek homoousios). Leo’s concept of ‘substance’ (substantia) perhaps needs some expla-
nation. The noun ‘substance’ was originally used by Tertullian in his discussion of Trinitarian doctrine. It could be made to stand for two
Greek concepts: those of ‘essence’ (Greek ousia), and ‘nature’ (Greek physis). The orthodox Trinitarian doctrine endorsed by the first two ecumenical councils accepted that the Trinity was one essence (ousia) in three persons, namely the persons of God the Father, Jesus Christ the Son, and the Holy Spirit. The next question, arising in the fifth century, was how a Christian should understand that essence in the one person (prosopon) of Jesus Christ. Christ’s essence was necessarily both human and divine, since Christian councils had defended his true humanity already against the teaching of the Docetists and his true divinity against the teaching of Arius. Did that make it divided? Could the human really be separated from the divine, or were they mixed together in Christ in such a way as to be indistinguishable? Leo’s solution was to understand them as ‘twofold’ (duplex). He occasionally used the phrase ‘consubstantial with the Father, consubstantial with the mother’ to express this idea (e.g. ep. 30.6). Leo maintained that acceptance of this doctrine was essential for salvation: ‘For it does no good to call our Lord, the son of the blessed virgin Mary, a man, if he is not believed [to be] a man of the same race and seed, of whom it is preached in the beginning of the Gospel’ (ep. 30.1, PL 54: 787B). In a letter sent to Theodosius II on the same day as Leo sent the Tome to Flavian, he describes the Tome as ‘a rather full treatment of what the Catholic Church everywhere believes and teaches concerning the mystery of the Lord’s incarnation’ (ep. 29, FOTC 34: 107). In the Tome, Leo presumed to speak for the whole church. He did not see it as presumption, of course, merely his natural prerogative as the incumbent of the see of St Peter. When discussing the nature of Christ, Leo usually used two terms
interchangeably: ‘substance’ (substantia), and ‘essence’ (essentia). Both had to do with that essential part of Christ’s being that was both human and divine, more than a soul and more than his personhood. The term ‘nature’ (natura) was, however, preferred in the Tome to Flavian and in other letters of 449, with the exception of Letter 31.2
The implications for Leo’s soteriology of the idea of twofold consubstantiality were serious. Like other fathers influenced by the teachings of the second-century Irenaeus of Lyons, Leo believed that ‘what is not assumed is not healed but what is united to God is saved’, in the words of Gregory of Nazianzus.3 That is to say, what Christ did not take up from human existence in his incarnation could not be saved by his death and resurrection. The idea was that if Christ were not fully human, as we are fully human, then all of humanity would not be redeemed by his sacrifice on the cross. This was the only way for Christ to defeat the devil and vanquish his demonic power over
human beings. A novel theme in Leo’s homilies and dogmatic letters is the devil’s right to power over humanity: the basis of the devil’s dominion over human beings before Christ’s saving act was Adam’s voluntary enslavement to sin. By causing suffering and pain for the sinless Christ, the devil exceeded his rights and thus forfeited his power over human beings.4 Leo is a biblical theologian rather than a speculative one, and so is concerned to show how Christ fulfilled the predictions of the Hebrew prophets, and how Christ’s personal history had been anticipated in the lives of the Old Testament saints (serm. 30.3-4) (Armitage 2005: 64-70). Leo’s understanding of how Christ fulfils the old covenant between
God and Abraham is also important. Christ instituted a new law by which all nations could be saved and become the ‘true Israelites’ (serm. 30.7) (Armitage 2005: 25-42). Leo’s idea of salvation was universal and communal: it was not for individuals but for the community as a whole. A new social contract had been implemented for those who followed Christ. Leo saw Rome as a Christian community, albeit a nascent and imperfect one. This ideal embraced both the city of Rome and its inhabitants, and Rome in a larger sense as standing for the civilisation introduced by the first Christian Roman emperor, Constantine the Great. Like Ambrose and the poet Prudentius in the fourth century, Leo believed that the Roman peace introduced by Augustus was the necessary precondition for the new dispensation. This notion contrasts sharply with the negative view of the pagan Roman empire expressed in Augustine’s City of God (McShane 1979: 68). The expansion of Roman territory in pre-Christian times and the imposition of the ‘Roman peace’ had allowed Christians the opportunity to spread their gospel far and wide and also to impose the faith on subject peoples. Forcible conversion, like that of the Goths, posed no moral conflict for Leo. What mattered was that the faith embraced was orthodox Christianity and not the Arianism of the Goths and Vandals, or any more heretical persuasion. Leo sought to make Christianity a truly civic religion.
