We know precious few facts about the life of Maximus of Turin. He was not a native of Turin, as Maximus himself implies in Sermon 33, and his clerical status upon arrival in the town is unclear. Gennadius of Marseilles’s On Illustrious Men (late fifth century) notes that Maximus was a bishop of Turin and that he died during the period when the reigns of the western emperor Honorius and the eastern emperor Theodosius II overlapped – that is, sometime between 408 and 423. Gennadius also describes Maximus as a competent preacher able to fit his discourse to any occasion or any biblical text. Neither a terribly significant figure from late antiquity nor the most gifted orator of his era, Maximus left behind a collection of more than a hundred sermons that, collectively, offer a glimpse into a rural Christian community in northern Italy during the late fourth and early fifth centuries. Here Maximus testifies to the region’s theological diversity; both heretics generally and “Arian heretics” specifically lurk around his community, as do pagans and lukewarm Christians. Indeed, he frequently complains directly to his congregation that they should attend his sermons with greater frequency.

The son of a praetorian prefect, well-educated and well-connected, Ambrose was governor of Aemilia and Liguria when, in 374, he was unexpectedly acclaimed bishop of Milan, though he was not yet even baptized. He was an able administrator, a benefactor of the poor and builder of churches, an innovative liturgist who composed hymns still sung today, and an eloquent preacher who dazzled congregants with allegorizing expositions of the Old Testament that drew on Philo, Origen, and other Greek writers. Ambrose used scriptural tapestries of his own creation to persuade his hearers into following a particular course of action, a competency on display in this letter. Ambrose’s voluminous writings were an important conduit of Greek thought to the Latin West. Major works include On the Sacraments and On the Duties of the Clergy. He also wrote texts dedicated to scriptural exegesis and to the promotion of celibacy and asceticism, especially among women. His theological treatises, more synthetic than groundbreaking, challenged Homoian views of the Holy Spirit and the Incarnation.

Augustine was plunged into the Donatist controversy upon becoming bishop of Hippo in 395. In the wake of the Diocletianic persecutions in the early fourth century, the Donatists had split from the group whom Augustine called and considered “catholics” (i.e., “worldwide Christians”), creating a schism in the North African church that lasted for well over a century. The very nature of the church was in dispute: Donatists believed that the church must retain its purity and holiness, separating itself from sinners, whereas catholics maintained that the church could tolerate the presence of sinners as long as consent was not given to their sin. Donatists believed that catholics were implicated in the sin of those who lapsed in the Diocletianic persecutions by handing over the scriptures to imperial authorities; they believed that only by retaining its purity in this way could the church guard against catholic contagion. Furthermore, they regarded any sacrament administered by a cleric in a state of sin as invalid, and accordingly former catholics entering their communion had to be baptized (for the first time, in their view).

Among his many duties as bishop of Hippo in North Africa, Augustine (354–430) oversaw the reception of converts into the church. When newcomers to Christianity were ready to prepare for baptism, they were designated as catechumens. The catechumenate was a period of training, often lasting several years, in which newcomers learned how to live as Christians. At the beginning of each Lent, those catechumens who wished to be baptized at the upcoming Easter would submit their names and thereby formally become “petitioners” (competentes). During Lent the petitioners engaged in a number of ascetical and ritual practices designed to complete their initiation into the Christian way of life. These included fasting, undergoing periodic exorcisms, and receiving special instruction from the bishop by listening to sermons that covered a broad range of Christian doctrine and practice. Two weeks before Easter, petitioners participated in a ceremony known as the traditio symboli, the “handing over” of the creed. At this ceremony the bishop formally recited the creed, with the expectation that afterward the petitioners would memorize it. There was a similar ceremony that “handed over” the Lord’s prayer (traditio orationis). At the Easter Vigil, the petitioners would “hand back” the creed (redditio symboli) and the Lord’s prayer (redditio orationis) by reciting them before the congregation and fully participate in the Eucharistic liturgy for the first time, in the course of which they received the sacraments of initiation: baptism, chrismation, and Eucharist. During the Easter octave – the eight days from Easter Sunday to the following Sunday, counting inclusively – the newly baptized, whom Augustine called “newborns,” would attend sermons that unpacked the meaning of the sacraments they had just experienced and received at the Easter Vigil.

What little we know about the Latin author Commodian comes directly from his own poems – the Instructions and the Apologetic Poem (also known as the Poem about Two Peoples). Gennadius (On Illustrious Men 15) mentions him but relies on Commodian’s poems just as we do. Commodian was most likely writing in North Africa, probably Carthage, in the third quarter of the third century. He has a deep affinity for and familiarity with Cyprian, and was likely a direct contemporary, though it appears he himself never held ecclesial office. Commodian seems to have been a layperson whose own journey from “frequenting the [pagan] temples” (1, 1.5) to becoming a “Law-inspired” – that is, “scripture-inspired” – Christian (1, 1.6) prompted him to make his own efforts to influence his various communities in Carthage. It seems likely that he identified as ethnically Syrian (hence the final poem’s title, where the author of the Instructions identifies himself as “the man from Gaza”), and that, prior to his time in Carthage, he spent substantial formative years in Aquileia.

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 lines of his verse survive).

Thascius Caecilianus Cyprianus – better known to history as Cyprian – converted to Christianity around 246 after a successful secular career as a rhetorician. Soon he was ordained to the priesthood and in 248 or 249 was consecrated as the bishop of Carthage. Not long after this, in late 249, the persecution of Emperor Decius broke out and Cyprian fled Carthage out of a concern that his church not be deprived of its bishop, as had recently happened in Rome and elsewhere. When the persecution ended in 251, in its wake there arose in Carthage and Rome several theological and pastoral problems, particularly over the readmission into the church of those who had lapsed in the persecution. Cyprian adopted a measured policy of readmitting the lapsed after a period of suitable repentance, and this policy was adopted also by Cornelius, the new bishop of Rome. He lays out this approach in On the Lapsed (De lapsis), written in 251. But laxists in Carthage, who supported the lenient readmission of the lapsed, and rigorists in Rome, who denied that readmission was even permissible, opposed the official policy, leading to schisms in both places.

Ambrose’s tenure as metropolitan bishop of an imperial capital brought him into considerable contact with the eastern emperor Theodosius I, who frequently resided in Milan during his visits to the West, especially from 388 to 391. Ambrose’s engagement with the emperor was confrontational. For instance, early in his stay, at a church service, Theodosius sought to take communion with the priests at the altar, as was the custom in Constantinople, but according to the church historian Sozomen (Ecclesiastical History 7.25.9), Ambrose told him to return to his seat. This was a harbinger of the complex power dynamic that would characterize the relationship between emperor and bishop in the coming years. In 390, after a general was murdered by rioters in the city of Thessalonica, troops were let loose on the city’s residents, many of whom were slaughtered.

As noted in the introduction to Hilary’s Sermon, Honoratus founded a monastic community sometime between 400 and 410 on an island off the coast of what is now Cannes in southern France. Then called Lerina, the island is now called Île Saint-Honorat de Lérins. Inspired by the desert fathers he had visited during his travels, Honoratus initiated at Lérins a style of monastic living that stressed individual ascetic pursuits within a communal context. It has been described as a monastery of hermits in community. As time went on, however, and due to the influence of the writings of Augustine and John Cassian – the latter dedicated his second set of Conferences to Honoratus and Eucherius (another monk of Lérins, who was chosen bishop of Lyon around 434) – the monastery of Lérins came to place more emphasis on the communal aspects of monastic living.

The Life of Hypatius was likely written in the mid-fifth century by Callinicus, the second abbot of the monastery that Hypatius founded across the Bosporus Strait from Constantinople. From a literary perspective, the text is a fairly conventional example of a late antique Greek hagiography; it owes much in structure, tenor, and phrasing to the period’s most well-known hagiography, Athanasius’ Life of Antony. Based on evidence internal to the narrative, Hypatius would have lived from 366 to 446 and would have, along with two companions, set up their community some three miles south of Chalcedon around 400 in an otherwise unoccupied compound that included an apostolic church (that doubled as a martyrium), palace, and monastery built by the imperial official Rufinus. During the early years of Hypatius’ residence here, the site hosted the Synod of the Oak, an event that ultimately deposed John Chrysostom, although Hypatius was personally absent during the trial. Two of the Egyptian monks known as the Tall Brothers – Ammonius and Dioscorus – died during their stay, and their remains were deposited within the church.

Between 400 and 410, Honoratus, the scion of a noble Gallic family, founded a monastic community on the island of Lérins (modern Île Saint-Honorat de Lérins, just off the coast of Cannes in southern France). A charismatic figure, Honoratus inspired many men from Gaul and elsewhere, including his relative Hilary, to take up the ascetic life at Lérins. Some years later, around 427 or 428, when the island monastery had become an unqualified success, Honoratus left to become bishop of Arles, although he died shortly thereafter in 430. His successor as bishop, Hilary, commemorated the first anniversary of Honoratus’ death in 431 with a sermon delivered to the Christian community of Arles on his life and virtues. Having only been in office for a year, Hilary used the sermon to provide a kind of apologia for his own episcopal leadership, presenting himself as Honoratus’ handpicked and personally trained successor. Hilary served as the bishop of Arles until his own death in 449.

This is the only work that survives by Socrates Scholasticus, a figure traditionally believed to be a lawyer, despite no evidence indicating as much. His Ecclesiastical History was likely written late in the reign of Theodosius II, covering the period from Emperor Constantine to Emperor Theodosius II (from 305 to 439). Like his fellow fifth-century historians Theodoret of Cyrrhus and Sozomen, Socrates, who likely wrote his work before they wrote theirs, picks up his narrative of church history where Eusebius of Caesarea left off in his Ecclesiastical History and tracks the activity of bishops, priests, monks, emperors, imperial officials, and military figures as they operate within the then-new cultural matrix of an imperialized Christianity. He draws on the original writings of many of his subjects and incorporates material from Eusebius of Caesarea’s Life of Constantine, Rufinus of Aquileia’s Ecclesiastical History, and the lost work of Gelasius of Caesarea, among other sources. While Socrates avoids the triumphalist tone that defined the writings of his predecessor Eusebius, he nevertheless uses his work to argue that the world benefits from a strong relationship between Christian worship and state power.

Caesarius was born in the Burgundian city of Chalons-sur-Saône around 470. At the age of seventeen, he entered the island monastery of Lérins. But after a few years he was sent to Arles to regain his health, which he had ruined through intense asceticism. Aeonius, the bishop of Arles and a relative of Caesarius, ordained him to the diaconate and the priesthood, then appointed him the abbot of Trinquetaille, a monastery in the suburbs of Arles. When Aeonius died in 501 or 502, Caesarius succeeded him as bishop, a position that embroiled Caesarius in the politics of the area, in which the interests of the Visigoths, the Franks, and the Gallo-Romans were often in conflict. He became the most prominent bishop in the Gallic church when pope Symmachus of Rome confirmed him as metropolitan and papal vicar for Gaul in 514. He presided over a number of synods and councils in Gaul, the most important being the Council of Orange in 529, which condemned the teaching on grace that predominated in southern Gaul in favor of a modified Augustinian position.

Tertullian (ca. 170–225) was a Christian writer whose work provides some of the scant evidence we have for North African Christianity of that era. Little is known about his life, and details from later Christian writers like Jerome and Eusebius are dubious at best. What we can say with certainty is that Tertullian became increasingly rigorist over the course of his life – with respect to ethics, doctrine, and communal boundaries. Indeed, his increasing rigorism aligned him with a broader movement of rigorists in the North African Christian community, the Church of the New Prophecy (traditionally known as Montanism). This Christian revivalist movement began in Phrygia during the mid-second century but migrated to various regions throughout the Mediterranean basin, including Carthage. The Church of the New Prophecy understood the history of salvation as one marked by increasingly intense moral rigor: the Old Testament patriarchs were allowed conduct (polygamy, for example) that was prohibited by Jesus and the apostles in the New Testament. Indeed, God’s revelation continued in the oracular statements of “new prophets” like Montanus, Priscilla, and Maximilla, statements that were understood as equally authoritative utterances of the Spirit.