The Ekthesis had made monothelitism imperial orthodoxy in 638 and remained in force under Constans II, who assumed the throne in 641. While this doctrine was apparently popular in some regions, it faced stern opposition from North Africa, whither Maximus and his companions had fled and whence they mounted a dyothelite insurgency. Anti-imperial fervor even inspired the North African exarch Gregory in 646/7 to proclaim himself emperor against Constans II. Faced with this emergency, in 647/8 Paul, the patriarch of Constantinople, in the name of Constans II, published a compromise document known as the Typos, which in this context means something like “general instruction.” This document replaced the Ekthesis that had previously hung in the narthex of the Great Church. The Typos forbade all discussion of Christ’s activities and wills, aiming to set the clock back to the time of the fifth ecumenical council (553). However, a synod the following year (649) at the Lateran in Rome rejected both the Typos and the Ekthesis, which led to a major clash between imperial forces, on one side, and Martin of Rome, Maximus the Confessor, and their allies, on the other.

The surviving body of writings from Augustine includes a large corpus of letters, most from his time as bishop of Hippo in his native North Africa. The letters, which include briefs to as well as from Augustine, cover a remarkable range of topics. Letter 137 is part of a fascinating dossier of letters from around 412 between Augustine and the talented young aristocrat Rufus Antonius Agrypnius Volusianus. Volusian, as we will call him, was the son of the famous Christian patroness Melania the Elder, but not himself a Christian. He did not hesitate to share his doubts about Christian teaching with Augustine, who must have been his senior by at least thirty years. At one particular meeting of young aristocrats, which Augustine mentions in Letter 137, Volusian encountered objections to the Christian doctrine of the incarnation, which he vowed to forward to Augustine for a reply.1 The main issue Volusian notes is the seeming incongruity in the doctrine, which posits that the ruler of heaven was confined in the tiny body of an infant and underwent the ordinary experiences of a human being.

The letter presented here is part of a corpus of Greek writings by an unknown Christian author of the late fifth or early sixth century. The author wrote under the pseudonym of Dionysius the Areopagite, who according to Acts 17:34 converted to the faith after hearing the apostle Paul’s preaching in Athens. The texts penned in this persona would exercise an enormous influence on Christian thought up until the time of the Renaissance.

The conversion of Augustine of Hippo (354–430) to catholic Christianity in 386 is a famous story. After he was baptized in Milan, he abandoned his post as professor of rhetoric in that city, and he and his friends formed a small, quasi-monastic circle devoted to the philosophical life of study and asceticism. After the group moved to Augustine’s native North Africa in 388, he composed a series of responses to questions posed by his confrères, writing his answers up in the style of the question-and-answer tradition of Greek and Latin literature.

In 610 Sergius became patriarch of Constantinople and later the same year crowned Heraclius as emperor (r. 610–641). Sergius would remain central to imperial religious policy until his death in 638. These were tumultuous years, as the empire faced incursions from Avars to the northwest and, more threateningly, from the Persian shah Khusro II to the east. After Khusro’s initial success, including the capture of Jerusalem and the True Cross, Heraclius and his allies defeated the shah in 627 and restored the True Cross in 630. In the coming twelve years, however, the empire would lose Syria, Palestine, and Egypt to a new invader, the Arab tribes. Internally, Christians of the eastern Mediterranean were divided. In 638 Sergius penned a fateful Ekthesis or “exposition” of faith, in the hopes of ending certain disputes among Chalcedonians. The Ekthesis, issued in the name of Heraclius, repeats the prohibition initially issued in 633 in the Psēphos on teaching either a single or two activities in Christ (the positions known, respectively, as monoenergism and dyoenergism).

A gem of early Christian oratory, Proclus’s first homily on the Holy Virgin draws on the emerging tradition of festal homilies such as we see in Basil of Caesarea’s Homily on the Holy Birth of Christ and Gregory of Nyssa’s Homily on the Savior’s Nativity1 and addresses the crises of his day. Proclus was bishop of Cyzicus in 430 when he proclaimed this homily in the presence of his archbishop, Nestorius, who had been installed by Theodosius II on the episcopal throne in Constantinople. The occasion, it appears, was the feast of the Virgin that had recently been instituted in Constantinople for December 26. Defying Nestorius, Proclus unequivocally defends the language of Mary as Theotokos, which for him safeguards what he calls here the “coupling of natures,” divine and human, in Christ, the “incarnate God.” To name Mary’s role in effecting this union, Proclus draws on a trove of imagery at once exuberant and focused. Mary is, following the Cappadocians, the incarnation’s “workshop,” but also a bridge, a field, and a temple.

If Christ exists in two natures, as the Council of Chalcedon proclaims, does it follow that he performed distinct classes of activities, human and divine? If you say yes, you are a “dyoenergist” (from the Greek dyo energeiai, “two activities”); if you insist that Christ performed activities of only one class, and thus answer in the negative, you are a “monoenergist” (from the Greek for “one activity”). The dyoenergist position was defended in memorable fashion in the Synodical Letter of Sophronius of Jerusalem from the year 634. To understand this letter, as well as several documents that follow in this volume, we must set the historical context and map some difficult conceptual terrain.

In the years following the death of Basil of Caesarea in 378, his younger brother Gregory of Nyssa (ca. 335–ca. 394) emerged as a leading Christian intellectual. Following his brother, Gregory wrote against Eunomius, the Pneumatomachians, and Apollinarius. He attended various synods, including the Council of Constantinople in 381. He was cited in a law of the emperor Theodosius dated July 30, 381 as one of the paragons of orthodoxy in the Eastern Roman Empire and was sent by the emperor on missions to supervise episcopal affairs as far as the province of Arabia. Dozens of his writings on various themes of Christian doctrine and practice have survived. As bishop, one of his roles was to preach at the annual feasts. The current sermon is one of the earliest pieces of evidence for a feast of the Nativity on December 25 separate from the Epiphany on January 6 – at the time this was a relatively recent distinction. We are uncertain as to which year Gregory delivered this Christmas homily, but a reasonable guess has been made that it was 386.

Justin hailed from the city of Flavia Neapolis, the modern West Bank city of Nablus, in the Roman province of Syria Palestina. According to his own account in the Dialogue with Trypho the Jew, Justin became a professional philosopher of the Platonist school before adopting Christianity as the true philosophy. From his pen, we have a few surviving works: the First and Second Apologies, which some scholars believe to have been originally a single treatise, probably written in the first half of the 150s, and the Dialogue with Trypho the Jew, written perhaps around 160. He also wrote a refutation of Marcion, which has not survived. Since antiquity, the philosopher Justin who authored these texts has been identified with the Justin who was martyred in Rome, as described in the Acts of Justin. According to that text, Justin was a Christian philosopher who taught in the city of Rome for many years prior to his execution, perhaps in the middle of the 160s.

In the late 410s or early 420s, in an epistle that is no longer extant, a monk in Gaul named Leporius, motivated by a desire to avoid attributing change and the human condition to God in the incarnation, wrote that he was disinclined to confess that God was born of a woman. Instead, he preferred to say that a perfect human being was born along with God rather than as God. The epistle sought to demonstrate this basic point and related Christological consequences through the interpretation of several key passages of scripture. But the form of Christological dualism that he advocated soon came to be deemed aberrant. When he refused to recant his views, Proculus, bishop of Marseilles, and Cillenius, a bishop of an unknown see in southern Gaul, formally rebuked Leporius in circumstances that remain unclear, and expelled him from Gaul. Along with two disciples named Domninus and Bonus, he took refuge in North Africa with Augustine.

This chapter highlights the formative role of Platonism in the making of Christian doctrine. It argues that Platonism’s greatest substantive influences on Christian Trinitarian theology lay in the area of participation metaphysics, as well as in inspiring the more general theological dictum of divine immateriality and intelligibility. Early Christian authors discussed include: Athenagoras, Theophilus, Clement of Alexandria, Marius Victorinus, Augustine, Theodoret, Cyril of Alexandria, Gregory of Nyssa, and Eunomius. The claim that the Christian creator–creature distinction competed with the Platonic intelligible–sensible distinction is examined and rejected.