Clerics and monks were originally chalk and cheese. The clergy were an increasingly complex system committed to highly structured hierarchy – but there were unresolved uncertainties about the precise form it should take. The chapter discusses for instance the clerical cursus honorum, reactions against fast-track promotion, and the bigamia rule against clerics in higher orders marrying more than once and the rule’s relation to pagan marriage. The apostolic see was called in to clarify problems arising from these systems and also from the awkward relation between clerics and monks. Monasticism was an unstructured movement, sometimes out of control, at one point banned from towns by imperial law. The interpenetration of the clerical and monastic systems only intensified the challenge of integrating them. The problem would recur in different forms throughout the history of the Latin Church, and the difficulty of coordinating the two overlapping systems had the unintended consequence of strengthening the papacy, constantly called in to integrate monks within the religious legal system and adjust the differences between the two religious elites. The process is already in evidence with the earliest papal jurisprudence.

As well as passing on or reaffirming decisions made at Nicaea, the apostolic see around 400 CE was dealing with issues the council had not addressed about who was entitled to administer a given ritual and when it was appropriate to do so. Questions arose notably about the ritual called consignatio, baptism, fast days in the week, a death ritual, and about marriage, adultery, and the Eucharist. These were problems without self-evident answers, and finding solutions might involve considerations both of principle and practicality.

The apostolic see was asked how ritual systems, especially the system of clerical ordination, should be coordinated with the rules for the reception of repentant heretics. The main ritual system in question was clerical ordination, but baptism was drawn into the discussion. The main heresies in question were the Novatians, the followers of Bonosus and (less prominent) some Arians. The actual content of these theological heresies was hardly discussed in the papal responses. In terms of modern analytical ‘etic’ concepts, the responses are legal rather than theological. The last part of the chapter explains this conceptual distinction – between ‘legal’ and ‘theological’ – as it will be used throughout the book. Medievalists sometimes assume that canon law and theology were indistinguishable before the late twelfth century. It is true that they had constituted a continuum in the eleventh and twelfth centuries. When we look further back to late Antiquity, however, we find that a de facto distinction had emerged, even if around 1100 it would be submerged for a time.

That papal responses about Pelagianism belong to a specifically legal domain is a secondary conclusion of the chapter. The primary conclusion can be integrated with a central argument about the origins of the first papal jurisprudence, viz., that it was demand-driven, and that the demand was driven by uncertainty. We should not be surprised at uncertainty in late Antiquity about grace and free will when modern scholars write in such different terms about Augustine. Many modern people prefer Pelagius, but Augustine’s understanding of grace won the assent of intellectuals like Gottschalk in the ninth century, Bradwardine in the fourteenth, and Luther and Calvin in the sixteenth, and it continued to have adherents within Catholicism, even after the Council of Trent. Self-evident the solution to the argument was not. Given the violently opposed views, in this apparently purely Western controversy, it is not surprising that the apostolic see was asked for a response. Baffled by the paradox of divine omnipotence and human free will, it did what it would do in subsequent centuries: step back from acceptance of Augustine’s late views, without breathing a word of criticism against him.

In late Antiquity there were too many hierarchies for comfort. How to coordinate them was not self-evident. This chapter looks at the apostolic see’s efforts to resolve a case where imperial law clashed with episcopal law, to regulate relations between the imperial and episcopal hierarchy (in which the bishop of Rome was included), and to coordinate hierarchy of command with status hierarchy. Indissolubility of marriage (papal versus imperial rulings), the ban on members of the curial class entering the clergy, and metropolitan episcopal jurisdiction are discussed.

Tensions arising from the establishment of monasteries in Gaul by John Cassian get associated in a long decretal of Celestine I with Cassian’s mild but firm critique of Augustine of Hippo’s views on grace and free will. These topics are the only core theological subjects discussed at length in the Dionysiana and Quesnelliana collections: the latter has three fascinating letters of Innocent I to African bishops, apparently endorsing their hard-line views on grace and (corrupted) nature, but in fact significantly silent on key points, stoppping short of some hard-line Augustinian positions.

Rather than providing a detailed survey of recent research (since this is available elsewhere), the chapter concentrates on the key contributions to the field of Erich Caspar, Charles Pietri, Geoffrey Dunn, and two historians influenced by Michel Foucault: Kristina Sessa and George Demacopoulos.

The celibacy within marriage of the secular clergy may have been a response to the celibacy of monks, because monks were becoming prominent in Western Christianity in the fourth century. Originally lay, without clerical orders, their relation to the ordinary clergy, while not hostile, was complicated and problematic from the start. What happened when clerics became monks or vice versa, for instance? Dealing with the interactions of these two elites would be a central role of the papacy ever afterwards. In the early papal legislation we see the start of this mediating role.