Ibas was the bishop of Edessa from 435 to 457. In 449 the second Council of Ephesus deposed him and several other bishops for their dyophysite (“Nestorian”) views, but the Council of Chalcedon exonerated and reinstated him in 451. A century later he would gain infamy as the author of one of the Three Chapters – the letter to the otherwise unknown Persian cleric Mari translated here – that Emperor Justinian had condemned at the second Council of Constantinople in 553. Written in the mid-430s after Cyril of Alexandria and John of Antioch had agreed to the so-called Formula of Reunion, Ibas’s Letter to Mari is important for its succinct narrative account of the Council of Ephesus in 431 and the reconciliation between Cyril of Alexandria and John of Antioch in 433, as well as for the window it provides on the Christological divisions within the Christian community in Osrhoene.

Philoxenos of Mabbug (ca. 440s–523) wrote prolifically in defense of his theological positions. Especially important to him was the unity of Christ’s nature, a position he thought that the most powerful Christians of his day had mistakenly abandoned. Written toward the end of his life and after his removal from his office as bishop in favor of a supporter of the Chalcedonian Definition, this letter outlines the fine details of Philoxenos’s miaphysite Christology. For him, the process by which the Word had become human was key for understanding the entirety of Christianity; the questions about how and when this “humanification,” as he called it, had happened are pursued in the letter to an extent that can seem excessive, but the mechanics of humanification mattered to Philoxenos for two reasons. First, a mistaken idea about this process could lead one to think wrongly about the status of Christ, that of his human mother Mary, and about the efficacy of salvation itself. Second, getting the details of humanification wrong could lead people to think that, in addition to the Trinity of Father, Son, and Holy Spirit, there was a fourth deity, named the Lord or the Son, who resides outside the Trinity.

Justin II became emperor upon the death of his uncle Justinian. During the first eight years of his reign (565–573), that is, before he descended into madness, Justin worked hard to establish a foundation on which the various Chalcedonian and anti-Chalcedonian communities could reconcile. He convened a series of conferences that, despite their contentiousness, culminated in Justin issuing this edict in 571. Sometimes labeled the Second Henotikon because of its similarity in aim and strategy with Emperor Zeno’s Henotikon from nearly a century earlier, this edict drew heavily on Emperor Justinian’s Edict on the Orthodox Faith from 551 with a few crucial differences. Justin II deemphasized “two nature” language and shifted toward a “one nature” formulation: he insisted that God the Word was hypostatically united with the human nature to the extent that the two natures of Christ could only be distinguished theoretically. In fact, most of the edict is little more than a string of quotations from Justinian’s Edict on the Orthodox Faith, carefully modified to lesser or greater extents and subtly selected and woven together to express a Christology that could be the basis for reconciliation.

In the uproar in the moments immediately after Eutyches was excommunicated at the Home Synod of Constantinople on November 22, 448, the disgraced archimandrite tried to appeal to a council of the bishops of Rome, Alexandria, Jerusalem, and Thessalonica. His request was ignored, but soon after the synod, likely within weeks of it ending, Eutyches wrote letters to the bishops of these major sees making the same request. In his letter to Pope Leo of Rome – which alone survives of all those sent to the bishops, though they must have been very similar – Eutyches gives a fascinating account of the Home Synod from his perspective. Unsurprisingly, he depicts Flavian as corrupt and himself as the victim of a conspiracy to destroy him. His basic narrative does not deviate significantly from the sequence of events found in the acts of the seventh session of the Home Synod, but Eutyches gives further details and even mentions a few things that were not recorded in the official acts. For example, we learn that he had prepared a statement to read when he first appeared at his trial, which he calls a “profession of faith,” but Flavian disallowed it.

John Cassian is more renowned for his seminal monastic writings than for his polemical tract against Nestorius. Around 380 Cassian traveled from the Roman province of Scythia Minor (modern-day Dobrudja) to Palestine, where he lived as a monk in Bethlehem for a few years. Around 385 he departed for Egypt to live among and learn from the Egyptian anchorites. In 399 or 400 he was forced to leave Egypt in the wake of a controversy that had reached violent proportions, when Origenist monks questioned the validity of Anthropomorphite theology. He accompanied the exiled Origenist monks through Palestine to Constantinople, where John Chrysostom ordained him to the deaconate. Toward the end of 404 the supporters of Chrysostom sent Cassian to Pope Innocent of Rome with information that exonerated the archbishop of some of the charges made against him. Chrysostom had been (falsely) accused of crimes ranging from excessive punishment and harassment of the clergy to gluttony and refusing to pray either inside or outside of the church.1 Eventually Cassian settled in Gaul (France), near Marseille.

The Council of Ephesus was the culmination of two years of machinations on the part of Cyril of Alexandria to isolate Nestorius of Constantinople both theologically and ecclesio-politically.1 This required a high degree of coordination between the sees of Alexandria and Rome as well as with Emperor Theodosius II. But from start to finish the Council of Ephesus unfolded in a way that no one could have anticipated, as highhanded maneuvering and factionalism destroyed any possibility of collaborative deliberations. A counter-council even met in opposition to the majority council. In the end Nestorius was deposed, but Cyril himself was too, at least for a time, and temporarily placed under house arrest in Ephesus. Furthermore, the council did not resolve the Christological issues that had pitted Cyril and his allies against Nestorius and his supporters; rather, the council only exacerbated the divisions. It would take nearly two years for a compromise to be reached, in 433, when the Formula of Reunion was issued.

On November 30, 430 Cyril of Alexandria, acting on behalf of the churches of both Rome and Alexandria, had his Third Letter to Nestorius delivered to Nestorius, openly accusing him of heresy.1 To this letter Cyril appended the Twelve Anathemas, Christological propositions threatening with excommunication everyone who did not subscribe to them. Being thus threatened with excommunication by Rome and Alexandria, Nestorius swiftly wrote a letter to his friend and compatriot John of Antioch, asking for advice.2 John then asked two prominent bishops from the Antiochene milieu, Theodoret of Cyrrhus and Andrew of Samosata, to respond in writing to Cyril’s Twelve Anathemas.

This anonymous letter to the otherwise unknown Diognetus is an early Christian apology in epistolary form. Since the seventeenth century it has been included in the collection of early Christian writings known as the Apostolic Fathers. Most scholars suggest a date between 150 and 200 for its composition – that is, at least for sections 1–10. The original text breaks off before its conclusion, and sections 11–12 were apparently appended at a later date from some other work. Sections 1–10 are addressed to an inquirer who wants to learn more about Christianity, whereas sections 11–12 appeal to Gentile converts to Christianity. The apologetic intent of the epistle is evident from its first part where the author mocks paganism and Judaism, emphasizing instead the distinctiveness and superiority of Christianity in terms of way of life (sections 2–6). In addition to section 1, translated below are sections 7–12. In sections 7–10 the author explicates the role of Christ in God’s plan of salvation. Particular stress is placed on the necessity of acquiring the knowledge of God revealed by Christ and the moral obligation that it entails, which is described as imitating God.

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.

Gregory of Nazianzus (ca. 330–390) was one of the famous “Cappadocian Fathers” (along with Basil of Caesarea and Gregory of Nyssa). Gregory was not only an important ecclesiastical leader – indeed, he acted as bishop of several cities and briefly presided over the second Council of Constantinople in 381 – but also an innovative theologian. His understanding of the Trinity helped to articulate and publicize pro-Nicene theology in the 370s and 380s, and his Christological ideas had enduring effects on later Christian thought. Perhaps the most underappreciated aspect of Gregory was his literary genius. Highly trained in classical texts, he was an accomplished epistolographer (more than 240 of his letters survive) and poet (nearly 20,000 of his verses survive). The text presented below – Letter 101 to the presbyter Cledonius – was probably written in the spring of 382 or the spring of 383. Although quite long, it was indeed a genuine letter conforming to a new epistolographical type that developed among Christian leaders in the second, third, and fourth centuries, a type in which an author could explicate exegetical, moral, or doctrinal issues at (sometimes great) length.

The three letters that follow highlight the fact that the Nestorian controversy had as much to do with ecclesiastical politics as it did with theological debate. Indeed, these letters, despite their brevity, illustrate one of the main reasons why Nestorius lost his struggle against the bishop of Alexandria, namely, his failure to draw Bishop Celestine of Rome to his cause. The primary purpose of the first letter, probably written in late 429, was to seek from Celestine information about several clerical exiles who had come to Constantinople from the West. These bishops, including most prominently Julian of Eclanum, had, as a result of the efforts of Augustine of Hippo, been deposed for adhering to the views of Pelagius regarding sin and salvation. Nestorius’s report to Celestine in the first letter hints at his intention to reopen their case, an action that he should have realized the bishop of Rome would not look kindly upon. This intention becomes more explicit in the second letter, written perhaps in early 430, as Nestorius complains of the lack of response from the Roman leader and insists that Celestine send him the dossiers used in the deposition of the Pelagian bishops.

This homily, like most of Jacob’s other homilies, begins with a long introduction. The passionate feeling of sorrow at the discord caused by the council which is expressed in the homily speaks for itself. It is, however, a little hard to discern the force of the biblical testimonia adduced (lines 116–126) in favor of the author’s standpoint, since these are standard testimonia with which any side in the controversy would presumably have been happy. Yet there is also a clear statement of the reasons why the council was unacceptable (lines 143–150): it is the dividing up of the properties, ascribing them either to the human or to the divine nature. It was precisely the emphasis on this aspect in the Tome of Leo and the Letter of Ibas that led to the disapproval of these two particular documents of the council by the opponents of Chalcedon. What Jacob objected to was the suggestion of a schizophrenic Christ; hence the impassioned cry which Jacob puts into the church’s mouth in line 155: “The Son of God is one, he is one!” There is a radical difference of perspective here.

Born to a pagan family in second-century Syria, and well educated in rhetoric and philosophy, Tatian embraced the “barbarian philosophy” of Christianity and wrote numerous works after his conversion. He traveled extensively throughout the Mediterranean, making it as far west as Rome, where, according to his slightly later contemporary Irenaeus of Lyons (Against Heresies 1.28.1), he came into contact with the various teachings of Justin Martyr,1 Marcion of Sinope, Saturninus,2 and Valentinus. He would later return to eastern Syria and set up a school that would influence Christianity in the region for the next several centuries. He initially crafted the Diatessaron (a harmony of the gospels) for students in his school, but it became the standard “version” of the gospels in Syriac liturgy well into the fifth century. He also wrote a series of treatises on the ascetic life, reflecting a regional emphasis on sexual and dietary renunciation that would endure throughout late antiquity.

In the 260s the recently elected Antiochene bishop Paul of Samosata faced an offensive from fellow Syrian church leaders, ostensibly on account of his theological persuasions. In his Ecclesiastical History Eusebius of Caesarea reports that as soon as it became clear that Paul “held low and base views about Christ, contrary to ecclesiastical teaching, that he was in nature an ordinary human being (koinou tēn phusin anthrōpou genomenou),”1 a first synod was summoned (ca. 264), to which clergymen from across the empire hastened. Shortly after this synod, and probably after a few more, Hymenaeus of Jerusalem and five colleagues composed a letter full of ad hominem attacks against Paul and containing a creed that insisted on the eternity of the Son. Finally, at a synod that gathered in 268/269, Paul was cornered by Malchion, an Antiochene priest of great rhetorical skill, and was deposed.

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.

Simeon of Beth Arsham, who is known as the “Persian Debater,” was a defender of miaphysite Christology during the first half of the sixth century. The miaphysite position insisted on a formulation with one nature in Christ in contrast to the dyophysite (“two natures”) position, whether Chalcedonian or not. Simeon is one of the theologians, who, along with Philoxenos of Mabbug (d. 523), Severus of Antioch (d. 538), John of Tella (d. 538), and Jacob Burdʿoyo (d. 578), played a role in the eventual development of a distinct miaphysite church in the aftermath of the Council of Chalcedon (451).

The First Letter of Clement is an epistle addressed by the church in Rome to its counterpart in Corinth in response to an outbreak of factionalism there. In ancient sources it is ascribed to Clement, a leading figure of the church in Rome toward the end of the first century, but this attribution is now doubted. A late first-century date seems likely nonetheless, with most scholars placing the letter between 80 and 100 CE, and some more precisely in the mid-90s. The First Letter of Clement is thus one of the earliest extant Christian writings, as old as some of the documents that were later incorporated into the New Testament. It was greatly esteemed and extensively read in early Christianity; as late as the fourth century it was even regarded by some as part of the New Testament canon. Since the seventeenth century it has been included in the collection of early Christian writings known as the Apostolic Fathers.

Two works against the Council of Chalcedon are attributed to Timothy Aelurus. The first survives fully in Armenian and as a synopsis in a Syriac epitome; its title in Armenian is very long, so today scholars call it Against the Dyophysites or On the Unity of Christ. Timothy includes over three hundred quotations not only from authors whose views he opposed but also from works cited in support of his understanding of Christology. He also refutes the Definition of Faith promulgated by the Council of Chalcedon and Leo of Rome’s Tome to Flavian of Constantinople in this work, which was endorsed by the Definition. The second work survives in a single Syriac manuscript, which dates to before 562. It consists of four parts: (1) a section-by-section refutation of the Chalcedonian Definition, (2) a section-by-section refutation of the Tome of Leo, (3) a florilegium of quotations from the acts of Ephesus II chosen to demonstrate the bishops’ stunning change of mind at Chalcedon, and (4) a eulogy for Dioscorus of Alexandria along with an exhortation to persevere in the faith.

The Latin title, Epistula Apostolorum, was suggested by Carl Schmidt, the first editor of this previously unknown work. In chapter 2 eleven apostles are indeed named as the collective authors of this work, addressed to the entire worldwide Christian community, but its contents do not correspond to the apostolic or pseudo-apostolic letters of the New Testament. The major part of the Epistula records a dialogue supposed to have taken place on Easter morning in which Jesus answers questions put to him by his disciples in preparation for their future mission. The dialogue occurs within a narrative frame that includes a collection of miracle stories from Jesus’s childhood and ministry (chapters 4–5), a version of the empty tomb story together with an appearance to female and male disciples (chapters 9–12), and a concluding ascension narrative unrelated to the more familiar version in Acts (chapter 51). In many respects this text is more like a gospel than an epistle.