Reading Between the Lines: Toward a Methodology for Tracing Manichaean Echoes in the Epistulae of Augustine of Hippo

Abstract

Augustine of Hippo (354–430), one of the most influential theologians of Late Antiquity, spent nearly a decade in the Manichaean sect before becoming a central figure in the shaping of Western “orthodox” Christianity. While his major works such as the Confessiones and De civitate Dei have been extensively studied for their treatment of Manichaeism, the vast collection of his ca. 300 preserved letters (Epistulae) remains an understudied source for understanding this aspect of his intellectual and theological development. This article addresses that gap by proposing a methodology to identify both anti- and crypto-Manichaean themes in his letters. Drawing on phenomenological openness, hermeneutical perspective, and close reading, the study also incorporates genuine Manichaean sources and anti-Manichaean polemics to contextualise Augustine’s rhetorical strategies. The Epistulae, unpolished and situated in specific communicative contexts, offer a unique view of Augustine’s doctrinal positioning after his conversion. Traces of his Manichaean past re-emerge in vocabulary, argumentation, and theological emphasis. This is exemplified in Epistula 137 to Volusianus (411–412), which, without naming the sect, covertly critiques key Manichaean doctrines such as Docetism and materialism. These critiques align with extant Manichaean sources and may reflect Augustine’s awareness of latent Manichaean influence in Christian communities. By bringing the Epistulae into the broader discussion of Augustine’s anti-Manichaean engagement, this study highlights their value as a window into his theological evolution and pastoral strategy in a religiously contested environment.

Although Augustine’s Epistulae have long been overshadowed by his more systematic theological treatises, renewed scholarly interest in his letters was sparked by the pivotal 1981 discovery of thirty previously unknown letters by Johannes Divjak (Ebbeler 2019, p. 242). This discovery, alongside the subsequent reassessment of the epistolary corpus by figures such as Peter Brown,1 has gradually repositioned the Epistulae as central witnesses to Augustine’s intellectual and spiritual development. While recent scholarship has begun to explore the Epistulae in relation to such themes as North African ecclesiastical politics, scriptural exegesis, Augustine’s confrontation with Jerome, and his doctrine of grace—especially in the context of the Pelagian controversy (Ebbeler 2025)—an exhaustive study of the corpus remains a desideratum. Studies have illuminated the polemical use of letters against the Donatists and the Pelagians, highlighting how Augustine transformed epistolary exchange into an instrument of correction and ecclesial boundary-marking. Recent scholarship reveals the fruitfulness of a rhetorical approach to these dynamics. Jennifer Ebbeler has demonstrated that in his correspondence with the Donatists, Augustine strategically uses invective not merely to condemn but also to define himself and his community in contrast to his opponents. By portraying Donatists as violent and divisive, he implicitly casts the Catholic Church as peaceful and unified, thereby reinforcing broader ecclesiological claims. Furthermore, Ebbeler shows how Augustine’s tone and style of polemic vary depending on the status and disposition of the addressee, indicating a calculated effort to persuade rather than simply attack (Ebbeler 2012). Laurence Dalmon, in turn, has shown that Augustine’s letters to Pelagian sympathisers likewise adapt rhetorical invective to the needs of persuasion and theological instruction. Particularly in his correspondence with fellow bishops or wavering interlocutors, Augustine balances firm condemnation of Pelagian error with gestures of pastoral concern. As Dalmon demonstrates, Augustine uses polemic not as an end in itself but as a rhetorical tool within broader strategies of reconciliation, clarification, and ecclesial alignment (Dalmon 2015).

Yet, curiously, Augustine’s prolonged engagement with Manichaeism—arguably the first and most formative polemical context of his life and thinking—has not received systematic treatment within his epistolary corpus. In recent scholarship, Augustine’s Manichaean past has been a major focus, especially in relation to his theological and polemical works as well as his autobiographical Confessiones.2 Although scholars have identified Manichaean themes and references in Augustine’s oeuvre through comparative approaches, the Epistulae may offer an even more accurate and nuanced picture of his intellectual and spiritual development over time. Several considerations support this claim. First, the Epistulae span the entirety of Augustine’s post-conversion life—from 386 to 430—thus providing a diachronic record of his doctrinal reflections, pastoral priorities, and rhetorical strategies (Ebbeler 2019, pp. 242–43; Nehring et al. 2017, p. 9). Second, Augustine never fully edited or published the letters as a collection. While he began reviewing his sermons and correspondence near the end of his life, he was unable to complete this task due to his declining health and the demands of his episcopal ministry, particularly his polemical engagement with Julian of Eclanum (Ebbeler 2019, p. 241).3 As a result, the Epistulae preserve Augustine’s unrefined, spontaneous reactions to the theological and ecclesial tensions of his time, in contrast to the edited, hence possibly filtered, arguments of his treatises.4

Augustine’s Manichaean past left a lasting imprint on his thought and identity.5 As Matthew Drever has observed, many of his teachings were formulated reactively in response to Manichaean doctrines (Drever 2013, pp. 135–53). After his conversion, Augustine frequently faced suspicion and accusations of lingering Manichaean influence, as exemplified by his conflict with Julian of Eclanum. These allegations compelled him to distance himself repeatedly from his earlier affiliation and to present himself as wholly aligned with Nicene orthodoxy (Dupont 2023, pp. 26–27). This dynamic raises further questions about the nature and timeline of his conversion. While Augustine’s Confessiones portray his renunciation of Manichaeism in Book 7 and his Christian conversion in Book 8 as decisive moments, other writings—especially those composed shortly after his Milanese conversion in 386—suggest a more gradual process.6 For instance, in Epistula 4 to Nebridius, penned in that early period, Augustine admits that he is still learning to distinguish between intelligible and sensible realities.7 This indicates a layered intellectual journey from Manichaean dualism, through Neoplatonism, and ultimately to Nicene Christianity, a journey more complex than the radical volte-face suggested by his autobiographical account in the Confessiones. Brian Dobell has argued that Augustine only fully embraced Christianity around his episcopal ordination in 395, a decade after his Milanese conversion, and the letters invite a more nuanced reading of how his theological identity evolved over time (Dobell 2009, pp. 18–27).

Finally, from a methodological standpoint, recent scholarship encourages us to read Augustine’s letters not merely as private communications but as public and strategic interventions. As Jennifer Ebbeler has shown, Augustine employed the epistolary form as a tool of ecclesiastical discipline and doctrinal clarification, adapting rhetorical invective according to the status of his interlocutor to persuade rather than simply to condemn. For example, in his correspondence with the Donatists, Augustine’s polemic serves not only to attack but to construct a contrasting image of the Catholic Church as peaceful and unified.8 Likewise, Laurence Dalmon’s work on the African-Roman correspondence during the Pelagian controversy has demonstrated how Augustine combines pastoral concern with theological polemic, balancing sharp critique with efforts at reconciliation, especially in letters to wavering or influential figures. These rhetorical strategies can be fruitfully applied to the analysis of Augustine’s references to Manichaeism within the Epistulae, where polemic is not an end in itself but part of a broader effort to consolidate orthodoxy and affirm ecclesial identity by exorcising the lingering spectre of his past.

The present study thus proposes a new approach to Augustine’s anti-Manichaean engagement by focusing on his Epistulae, not only as theological artefacts but as rhetorical instruments situated within the broader matrix of ecclesial authority, personal identity, and doctrinal controversy. In doing so, it aims to uncover how Augustine, through the epistolary genre, navigated the persistent tension between repudiating his former allegiance and integrating the formative traces it left on his Christian theology.

1. The Texts Under Scrutiny—Augustine’s Epistulae

The Epistulae of Augustine constitute, in specific ways, an extraordinary corpus among his extant works. Written between 386 and 430, they trace Augustine’s life from his alleged conversion and baptism in 386/387 to shortly before his death in 430. Thus, covering the later part of his life, they offer unique insight into his activities as a converted Christian, and later a priest and bishop, as well as into the various struggles and affairs that shaped his career. The letters also reveal Augustine’s extensive network of friends and associates across North Africa and the wider Mediterranean, as well as his engagement with the challenges Christianity faced in the 5th century. Naturally, the Epistulae appear to continue his Confessiones, a view also supported by Jennifer Ebbeler (Ebbeler 2019, pp. 242–43). Augustine may well have intended the Epistulae to serve as a res gestae of his episcopal actions (Ebbeler 2019, p. 241). Despite this thematic and narrative continuity between the Confessiones and the Epistulae, it must be noted that Augustine never managed to revise his letters comprehensively, nor did he succeed in organising them into a cohesive collection.9 Due to the complexity of the transmission history, it remains difficult to determine how the collection was compiled or by whom. As such, the letters offer a rare opportunity to observe a “rawer” and “less refined” portrayal of the bishop of Hippo.

This unpolished character is particularly valuable when investigating Manichaean references and influences in the Epistulae. Because Augustine did not revise the letters later in life, he was unable to remove elements he might have considered theologically inappropriate or inconsistent with his “mature” positions. This gives modern readers a picture of Augustine ‘in the moment’, that is, as a thinker embedded in specific contexts, facing particular problems, and in the midst of intellectual development. For instance, Augustine appears differently in Ep. 4, where he is still a newly converted Christian grappling with Neoplatonic philosophy, compared to Ep. 55, where he addresses theological questions posed by Januarius. Rafał Toczko aptly compares such ancient letters to modern Facebook posts or blog entries: each text reflects the author’s position at a given stage of life, revealing his concerns, thought processes, and immediate context (Toczko 2017, pp. 154–55). In the case of Augustine, this makes the Epistulae a valuable resource for tracking doctrinal evolution, especially regarding Manichaeism. In this context, two epistolary collections on the Pelagian controversy are particularly illustrative of the interplay between theology and church politics. The first set (Epistulae 175–177 and 181–183) reflects how North African bishops, following the controversial acquittal of Pelagius and Caelestius in 415 by Eastern synods, strategically turned to Rome to safeguard their theological stance on original sin and grace. Though Pope Innocent I supported the African disciplinary decisions, he did so without confirming their core theological claims, revealing how both parties subordinated doctrine to political expediency. The second collection (Epistulae 214–216A and 225–26), written in response to unrest in monastic circles over Augustine’s views on grace and predestination, represents the culmination of his doctrine: the unmerited, antecedent nature of grace and divine election from the massa perditionis. This exchange, though theologically radical, provoked no immediate schism or official condemnation, yet it underscores how epistolary writing allowed Augustine to refine and defend his evolving theology in real time and in reaction to lived controversy. While a similar perspective might be gained by comparing treatises written at different stages of Augustine’s life, the Epistulae allow us to trace his development letter by letter, year by year.10

Yet, one might ask: why seek Manichaean references in the Epistulae, given that letters are typically more personal, informal, and arguably less theologically sophisticated than treatises? To answer this, we must consider the nature of ancient epistolography, including its communicative context and rhetorical design. Although letters simulate oral, personal communication, they are often highly rhetorical and carefully composed. Moreover, in antiquity, letters were frequently written with the expectation that they would be read aloud to an audience. A letter would be composed by the author or dictated to a scribe and then sent to the recipient and read in his presence and before others (Toczko 2017, p. 156). Libanius, a 4th-century rhetorician, once complained that the content of a private letter had become widely known.11 Gregory of Nyssa, in correspondence with Libanius, attests to the rapid dissemination of his letters.12 Augustine’s Ep. 121, likely written by Paulinus of Nola, reveals an awareness that the theological content might be received with amusement by Augustine and his audience.13 In Ep. 136, we learn, for instance, that Marcellinus was encouraged by Volusianus to read Augustine’s letter publicly.14 Epistolary texts were frequently re-read, which detached them from their original communicative context. Latin authors often collected their letters with the intention of broader dissemination. Cicero’s letters, for instance, were posthumously collected by others. Pliny the Younger carefully curated a collection of his own letters to showcase achievements relevant to his public image (Salzman 2019, pp. 21–23). Horace composed verse letters in dactylic hexameter, underscoring their literary and didactic purpose. Seneca the Younger employed the epistolary form for philosophical reflection, moving beyond its primary communicative function (Salzman 2019, pp. 29–30). The epistolary genre has held a central place in Christian literary traditions since the earliest communities. The letters of Paul and other figures form part of the New Testament and dominate the corpus of the Apostolic Fathers (Quasten 1986, pp. 40–42; Ehrman 2003, pp. 1–14; Divjak 2001; Klauck 2006, p. 441). The letters of Ignatius of Antioch, Athanasius, Ambrose, Jerome, Evagrius, Basil the Great, and Gregory of Nyssa have also survived. Importantly, many Christian letters were addressed to entire communities, underscoring their public character and didactic intent.15 For example, Dionysius of Alexandria, bishop in Corinth at the end of the 2nd century, wrote and sent general epistles to Christians around the Empire to speak against Marcionism (Klauck 2006, pp. 440–41). Augustine employed letters as a pastoral tool in various contexts, including outreach to heterodox groups such as the Donatists and Pelagians. Ebbeler interprets this use as a revolutionary redefinition of epistolary tradition, which had typically centred on personal or friendly exchanges. Toczko, in turn, highlights the strategic advantage of letters over live debate: they enabled Augustine to engage Christians outside his immediate context, without the polemical risks of treatises or confrontational gatherings (Toczko 2017, p. 170).

The latter doctrinal engagement points to a theological dimension within the Epistulae. Augustine did not restrict himself to private or disciplinary concerns; instead, he frequently addressed theological problems and articulated doctrinal positions, as the above-mentioned anti-(semi-)Pelagian letters clearly demonstrate. The epistolary form, however, inevitably shaped the mode of expression. Unlike in theological treatises, where he could develop extensive and refined arguments, the constraints of letter writing required conciseness and adherence to rhetorical conventions.16 This sometimes limited the complexity of his theological exposition. Nevertheless, precisely because of these constraints, and the contextual immediacy they preserve, the Epistulae provide insight into how Augustine communicated theological ideas to broader audiences. They allow the reader to witness Augustine’s theology in a more dialogical and pastoral setting, reflecting both his intellectual evolution and his theological reasoning in situ.

2. The Question of Manichaeism—How Is It Defined in the Context of Augustine’s Epistulae?

Having introduced the corpus under discussion, we may now turn to the question of Manichaeism within the context of Augustine’s Epistulae. As previously noted, the letters were composed between 386 and 430, i.e., after Augustine’s separation from the Manichaeans. Since no extant letter dates from his Manichaean period, what, then, does it mean to speak of Manichaeism in this corpus?

First, a distinction must be drawn regarding the nature of the thematic content. The issue involves tracing both anti-Manichaean and crypto-Manichaean themes and references. By anti-Manichaean, one should understand any letter, or part thereof, in which Augustine criticises or refutes Manichaean doctrines, either explicitly or implicitly. Conversely, by crypto-Manichaean, one should understand any letter, or part thereof, in which Augustine expresses ideas that bear some resemblance to Manichaean doctrines. The question here is not whether Augustine continued to adhere to Manichaean teachings after his conversion but rather whether traces of his earlier affiliation resurface in the letters or whether certain views conveyed in them betray lingering influences of his Manichaean past.17

The anti-Manichaean aspect of the Epistulae is arguably the more straightforward to study. Both explicit and implicit anti-Manichaean references are present. Among the overt instances, certain polemical letters have been identified by editors, translators, and the Scrinium Augustini research team, such as Epp. 7, 28, 32, 36, 55, 64, 75, 79, 82, 118, 140, 166, 222, 236, 237, and 259. In these, the Manichaeans are rebuked by name, making the polemical intent unmistakably explicit. The more challenging task lies in identifying those passages where Augustine refutes Manichaean doctrines without naming them, in a more covert and implicit manner. Such references may be scattered throughout the corpus and not immediately evident to the unprepared reader. For instance, any affirmation of Christ’s corporeality and incarnation may qualify, given Manichaeism’s adoption of a docetic Christology. Thus, when Augustine opposes docetic views, he may be indirectly targeting Manichaean doctrine, even if not overtly referencing it. For example, in Ep. 95 to Paulinus and Therasia, he emphasises the bodily nature of Christ’s resurrected body.18 Similarly, in Ep. 137 to Volusianus, Augustine explains the incarnation to a group of non-Christian intellectuals, offering arguments that implicitly counter Docetism.19 Consequently, this letter, too, may be read within an anti-Manichaean framework. Such refutations do not necessarily imply that the addressees were themselves connected to Manichaean circles. Rather, Augustine may have used these opportunities to present himself as a true Christian convert from Manichaeism, actively opposing the doctrines he once accepted.

Turning now to the second tendency, by crypto-Manichaean we mean any reference or idea in the Epistulae that aligns, however subtly, with Manichaean doctrines. This may occur at the level of language, concepts, or doctrinal stances and would reflect the residual influence of Augustine’s earlier affiliation. The term crypto-Manichaeism should not be taken to imply any secret adherence to Manichaeism or covert belief in its teachings.20 Rather, it points to the unintended influence of Augustine’s past on his current theological reflections (Coyle 1978, p. 53). Tracing such influence is significantly more challenging than identifying anti-Manichaean themes, since Augustine’s intellectual development was shaped by a variety of sources, including Classical literature, ancient philosophical schools, Neoplatonism in particular, and Christianity.21 As a result, the appearance of certain motifs or concepts can often be traced to multiple origins. Nonetheless, the fact that Augustine was a committed Manichaean during a formative period of his intellectual life would suggest that this background must have left a lasting imprint.22 Given the relatively unpolished and spontaneous nature of letter writing, the Epistulae may reveal these latent influences more readily than his more structured theological works.23

This raises a further question: what kind of Manichaeism did Augustine actually encounter in Carthage during his youth? Although some scholars regard Manichaeism as a distinct religion, Augustine himself experienced it as a Christian sect rather than a different religion (which he labelled ‘schism’) such as Judaism, as Johannes van Oort has argued (van Oort 2020, pp. 141–42; van den Berg 2010, pp. 2–3). Modern scholarship has shown that Christianity was one of the foundational layers of Manichaeism, not merely a religion from which it borrowed. Thus, Augustine’s eventual conversion may have involved less of a radical break than one might assume; it was more a process of adaptation, whereby incompatible elements were discarded and compatible ones were reinterpreted within an “orthodox” Christian framework (Coyle 1978, p. 53; Dobell 2009, pp. 18–27). Yet, such modern distinctions do not always clarify how Augustine himself perceived Manichaeism during his youth.

Indeed, the classification of Manichaeism posed a challenge not only to modern scholars but also to ancient and medieval authors. Byzantine legislation, for example, varied in its characterisation of the Manichaeans, sometimes identifying them as a sect akin to the Valentinians or Marcionites and other times as a schismatic group akin to Jews or pagans (Matsangou 2023, pp. 226–30). While Augustine lived prior to much of this legislation, such inconsistencies reflect a longstanding difficulty in categorising the Manichaeans. Christian authors and Roman authorities often labelled them a heretical sect, yet in broader public perception they were not sharply distinguished from other Christians (van den Berg 2010, pp. 2–3). As Jacob A. van den Berg has noted, Augustine likely encountered the Manichaeans in North Africa as little more than one Christian group among others. Even though many Church Fathers made considerable efforts to differentiate Christian orthodoxy from Manichaean doctrine, Roman society often regarded them as standing on the same religious footing. This supports the view that Augustine’s conversion involved the elimination of incompatible ideas rather than a wholesale abandonment of his prior worldview.

Yet, if Manichaeans were perceived as a Christian sect, why was Augustine baptised only after his conversion? One possible explanation is that he had never previously received baptism.24 However, as Rea Matsangou notes, Church legislation in the Eastern Empire required that converts from Manichaeism be re-baptised after explicitly renouncing Mani, his disciples, and their writings (Matsangou 2023, pp. 455–57). While such legislation postdates Augustine and pertains primarily to the East, it raises the question of how the Western Church treated former Manichaeans. Nonetheless, the notion that Manichaeism was viewed as a Christian sect helps to illuminate Augustine’s attitude toward his former beliefs and the manner in which he reshaped his theological commitments.

Finally, Augustine’s personal involvement with the Manichaean community deserves further attention. As he confesses in the Confessiones, he never progressed beyond the role of auditor.25 That is, he never formally completed the catechumenate required for full initiation into the sect (Coyle 1978, pp. 52–53). This limited involvement is reflected in his often vague or uncertain accounts of Manichaean rituals. For example, in his earlier works, Augustine shows a degree of uncertainty in describing the so-called ‘human semen eucharist’, as van Oort has shown. In contrast, in his later writings he treats the subject with greater clarity and confidence (van Oort 2020, pp. 65–66). In Contra Fortunatum, Augustine remarks that only the electi had full knowledge of the sect’s rituals, whereas he remained a mere auditor.26 Thus, he may not have had direct access to certain practices during his time within the sect. Yet in De Haeresibus, he describes the aforementioned ritual in detail, citing a legal prosecution in Carthage in which two Manichaean women revealed the practice.27 But, despite his limited initiation, Augustine nonetheless had access to significant elements of Manichaean life (Coyle 1978, pp. 51–57). As Johannes van Oort notes, auditores provided numerous services to the electi (van Oort 2020, pp. 385–87) and participated in communal gatherings, including chanting hymns and listening to doctrinal sermons.28 Therefore, Augustine’s past affiliation, however partial, must be considered when interpreting the content and tone of the Epistulae.

3. Problems in Developing a Method to Retrieve Manichaeism

Identifying explicit rejections of Manichaeism in Augustine’s corpus presents little difficulty. Far more elusive, however, are the implicit traces, whether of polemical opposition or of subtle, indirect influence. The search for such traces in the Epistulae necessitates a robust and nuanced methodological framework.29 Because this inquiry engages both the textual and conceptual dimensions of the letters, it must draw on the tools of both literary analysis and historical-theological interpretation in order to provide a comprehensive analytical strategy.

Within the domain of literary analysis, a distinction is made between close reading and comparative methods. Studying Manichaean traces in Augustine’s letters requires a multifaceted interpretive model that combines hermeneutic and archaeological approaches with phenomenological analysis. Specifically, such a model applies close reading techniques to excavate thematic layers within the Epistulae, thereby exposing anti- or crypto-Manichaean elements embedded in rhetorical substructures. These elements often exceed the letters’ immediate polemical or pastoral objectives, requiring an interpretive model attuned to latent intertextual signals and indirect polemics.

A key principle of this approach is to read the Epistulae through what may be termed a “Manichaean lens”, not as an imposition of a foreign interpretive framework but as a heuristic device intended to make visible dimensions that would otherwise be overlooked. The interpreter thus reads with an awareness of Manichaean cosmology, anthropology, and soteriology and is attentive to instances where Augustine’s formulations may signal convergence, divergence, or unresolved tension with such doctrines. These instances must then be scrutinised on textual, lexical, and doctrinal grounds, with particular attention to historical context and rhetorical strategy.30

Close reading is particularly indispensable in cases where Manichaean traces are not the primary concern of a given letter. Such traces may be embedded in stylistic or lexical patterns, in marginal rhetorical decisions, or in the articulation of broader theological claims. In these cases, the primary narrative of the letter may need to be put aside for a while in favour of a focused analysis of local textual phenomena.

Comparative methods, both literary and doctrinal, complement this textual approach. A reliable analysis of Manichaean influence in the Epistulae requires sustained dialogue not only with extant Manichaean sources but also with late antique anti-Manichaean literature (Fox and Sheldon 2010, p. xxi). Reference to genuine Manichaean texts helps avoid anachronistic or overgeneralised attributions of “Manichaean” themes to Augustine. While it remains uncertain which specific texts Augustine may have read during his association with the sect, extant Syriac, Greek, Coptic, and Latin sources remain indispensable examples of the doctrinal contours of Manichaeism as it developed and spread (Fox and Sheldon 2010, pp. xii, xxii–xxv).31

Similarly, early anti-Manichaean texts, such as those by Alexander of Lycopolis, Titus of Bostra, Epiphanius of Salamis, and Theodore bar Khôni, as well as the Acta Archelai, serve as valuable sources despite their polemical tone (Coyle 1978, pp. 10–18; Fox and Sheldon 2010, p. xii). Although traditionally undervalued, these works often cite or reflect genuine Manichaean teaching, and thus provide indirect access to material that may have shaped Augustine’s own understanding (Matsangou 2023, pp. 84–109, 496). Within Augustine’s oeuvre, the Confessiones and his anti-Manichaean treatises constitute vital comparative sources. They not only clarify his engagement with Manichaean ideas but also shed light on the rhetorical posture he adopts when confronting them.

At the lexical level, comparative analysis seeks to identify parallels in vocabulary and phraseology between Manichaean texts and the Epistulae. Particular attention is paid to whether Augustine repurposes specific terms, possibly subconsciously, as part of his theological articulation. Tracing such lexical continuities or displacements may uncover deeper intertextual dynamics and ideological transformations. This inquiry is further enriched by cross-referencing other works by Augustine, thereby offering a diachronic perspective on his evolving engagement with Manichaean themes.

Doctrinal comparison extends the analysis beyond terminology to conceptual structures. By juxtaposing key theological claims in the Epistulae with Manichaean doctrines, the study examines potential continuities, refutations, and unresolved tensions. While definitive claims of textual dependence are methodologically untenable in the absence of known source texts, conceptual parallels remain highly suggestive and may allow for a more differentiated understanding of Augustine’s intellectual trajectory.32

This methodological model, therefore, offers a framework for future research on the complex and layered relationship between Augustine’s epistolary theology and the Manichaean tradition. By integrating literary, doctrinal, and rhetorical tools, the approach aims to provide a reliable path for identifying both overt and covert traces of Manichaean discourse in the Epistulae while remaining attentive to the historical and theological particularities of late antique polemic and conversion.

4. Proof of Concept: Case Study of Epistula 137

Ep. 137 offers a particularly apt case study for testing the proposed approach. Composed around 411 or 412, the letter was addressed to Volusianus—a pagan intellectual, brother of Albina, and uncle of Melania the Younger. The letter’s primary context is the articulation of key tenets of Christian doctrine for a non-Christian audience, comprising Volusianus and his intellectual circle. While Manichaeism is not mentioned explicitly, and the immediate context does not suggest its relevance, a close analysis of the letter’s content and underlying concerns strongly indicates that it implicitly addresses Manichaean Christology. Ep. 137 belongs to a dossier of letters sent between Augustine, Volusianus, and Marcellinus, the Imperial Commissioner in North Africa. This dossier involves letters from Ep. 135 to 138 and concerns solely theological issues, like Christology, the validity of the Old Testament, and the problem of pagan sacrifices. Both Ep. 137 and 138 are Augustine’s direct responses to questions posed by Volusianus and Marcellinus in Ep. 135 and 136. At the first sight, this is a correspondence between a Christian bishop and pagan intellectuals. However, the invoked topics introduce an anti-Manichaean tone in the letters. Furthermore, it needs to be noted that Volusianus and his friends, as members of Carthage’s intellectual elite, might have had contact with members of the Manichaean Church, which was prolific in North Africa. Thus, Augustine took the chance to explain the differences between Nicene Christianity and Manichaeism (Decret 2009, pp. 153–54).

The letter follows a clearly structured progression. The opening paragraph, Ep. 137.1, contains general greetings and an apology for the delayed response. In Ep. 137.2, Augustine outlines the questions raised by Volusianus.33 Among them, the reader finds inquiries about the incarnation, how Christ entered Mary’s womb, how God could abandon the heavenly seat and the governance of the world while entering a child’s body, and how it was possible for him to feel the exact needs of any other human. Next, in Ep. 137.3, he emphasises the depth of the Christian doctrine and his inability to cover it entirely. In the following paragraphs, Augustine presents his Christological views. In Ep. 137.4, he begins his analysis of Christ’s incarnation, addressing the problem of how God entered a child’s body without relinquishing governance over the world. In the subsequent paragraphs, Ep. 137.5–6, Augustine touches on the subject of the soul as an analogy for God’s existence in the incarnated body. In the next section, Ep. 137.7, he emphasises God’s omni-existence, which is not confined by bodily limits, and in Ep. 137.8, he explains his nature. In the following paragraphs, Ep. 137.9–11, Augustine discusses how an incarnated God would need to consume food and how the assumed humanity relates to divinity. Finally, in Ep. 137.12, he presents the Christological definition of the hypostatic union. Paragraphs 13 and 14 are devoted to the problem of Christ’s miracles in the context of other ancient figures. In Ep. 137.15, Augustine recounts the promises and prophecies given to Israel, fulfilled in Christ. In the following section, Augustine writes about the Church fulfilling the prophecies, encompassing the known world. Paragraphs 17–20 focus on the ethical principles of Christianity, the power of the Scriptures, and political objections towards Christians.

Upon a first reading, one might conclude that Augustine’s Christological discourse was directed solely to a pagan audience, without any secondary interlocutor. However, the letter includes several statements that indirectly but unmistakably refute Manichaean doctrine. Doctrinally, Augustine also targets Docetism, a view widely held among Manichaeans (Matsangou 2023, pp. 36–38, 135, 141, 226–27; Rose 1979, pp. 21, 63, 120, 135; Coyle 1978, p. 46). The Kephalaia, for example, asserts Christ had a phantasmal body.34 Against this, Augustine insists on Christ’s real incarnation and birth from the Virgin Mary, both positions rejected by Manichaeans. He also emphasises the hypostatic union of the two natures in Christ, contrary to the Manichaean belief that the human body, formed from evil origins, trapped the divine soul and prevented its return to the realm of Light. Moreover, the epistle contains an implicit rejection of the Manichaean assumption that the divine is fundamentally distinct from and incompatible with corporeality (BeDuhn 2001, pp. 5–18; Matsangou 2023, pp. 256–63).

Yet the question remains: is a thematic comparison of ideas and arguments sufficient to conclude that Augustine covertly critiques Manichaean doctrine? At this stage, a focused reading of the letter must be supplemented by detailed textual analysis and a comparative examination of genuine Manichaean sources alongside anti-Manichaean polemics. Starting with the former, Ep. 137.4 contains a telling phrase: ‘God wasn’t poured into flesh.’35 This wording is striking, especially since Ep. 135, Volusianus’s earlier letter, contains no indication of a materialist conception of God. The Latin term infusus raises suspicion, as derivatives of fundere are found in Latin Manichaean texts and in Augustine’s other writings when addressing Manichaean themes.36 Comparable expressions appear in the Acta Archelai, using the Greek terms μίξις and σύγκρασις, or their Latin counterparts permixtio and coniunctio.37 The word flesh itself is frequent in both authentic Manichaean and anti-Manichaean sources.38 Augustine’s formulation suggests a materialist view of the divine that he aims to contest. Further in the same paragraph, he asserts that “this reasoning belongs to those who can only think about bodies…”.39 The latter assertion closely echoes his critique of Manichaean materialism in the Confessiones.40 His concluding image, that God does not permeate the world like air, water, or light, similarly evokes the Manichaean notion of the soul’s entrapment in matter.41

The motif of mixture reappears in paragraphs 11 and 12, where Augustine explains the hypostatic union through the analogy of the unity between body and soul in a person. Just as the soul uses the body to constitute a person, in the same way, God uses human nature to become Christ.42 Paragraph 11 is replete with terms derived from the verbs miscere and permiscere.43 Augustine also describes an auditor who distances himself from a corporeal understanding—namely, the idea that when bodies mix, they lose their integrity.44 The sentence is clear, expressing an anti-materialistic stance, but the precise terminology used invokes an anti-Manichaean context.

From a Christological perspective, Augustine emphasises that Christ truly assumed a human form, underlining the fact that he needed to sleep and eat.45 On this basis, he affirms that the divine nature assumed humanity without annihilating it (Moreau 1973, pp. 59–66). He then refers to certain heretics who refuse to recognise anything human in Christ.46 While these remarks might evoke Monophysite positions, the letter predates the Eutychian controversy. Interpreting these passages in the context of Manichaeism appears more appropriate. According to Manichaean teaching, Christ did not assume a real human nature but entered the world in a body that only appeared to be human, a claim found in the Acta Archelai,47 Titus of Bostra,48 the Sermon of the Great War,49 and Manichaean Psalms.50 Augustine’s insistence that Christ assumed a genuine human body directly contradicts Manichaean doctrines, which regarded the body as a creation of evil and thus rejected it. Moreover, his emphasis on human activities such as sleeping and eating reinforces his argument and further distances his position from the Manichaean claim that “he was not truly human.”

Concerning the subordinate theme of materiality, Augustine articulates a clear stance against the materialist conception of God. Deus infusus carni was already analysed in a previous paragraph, but the letter addresses this topic again in Ep. 137.8, where Augustine states: “Not through mass but through power is God great”.51 He proceeds to clarify that God, being free from any material form, is the creator and originator of all that exists. Augustine then asserts that this same God assumed human corporeality through the Virgin Mary, without violating her virginity. The Latin term moles, typically denoting a large material mass, serves here to contrast the Christian view of divinity with a materialist one, likely the Manichaean one.

Nevertheless, the question remains: why would Augustine engage in anti-Manichaean rhetoric in a letter addressed to an entirely different audience? There appears to be no immediate Christian addressee in need of such warnings. The answer may lie in Manichaean practices and in how Roman society perceived the sect. By 411/412, when the letter was written, the Edict of Theodosius had long since come into force, also affecting the Manichaeans. Although not subjected to severe persecution, their ability to operate was significantly curtailed (Matsangou 2023, pp. 189–209, 445–57). During this period, Manichaeans often anathematised their faith, formally joining the Catholic Church while continuing to practise their beliefs in secret. This behaviour was characteristic of the Manichaean missionary strategy, which relied on infiltrating target communities to spread their teachings covertly (Matsangou 2023, pp. 475–89). At the same time, Roman society grappled with how to categorise Manichaeism, alternately describing it as a religion or a sect. To Augustine’s contemporaries, Manichaeism was largely seen as a Christian sect, and its adherents were treated as fellow Christians (van den Berg 2010, pp. 2–3). Augustine himself encountered the sect in this way. Given that Volusianus and his circle lived in Carthage, they may have encountered crypto-Manichaeans still present in the city. Moreover, Manichaeism remained an appealing option among North African intellectuals, as mentioned above (Decret 2009, pp. 153–54). Although Volusianus’s letter contains no clear indication of such concerns, Augustine may have deemed it prudent to pre-emptively address the issue, subtly outlining how Christian doctrine should be understood. While this remains a hypothesis, the preceding analysis confirms the presence of covert anti-Manichaean themes in the Epistulae and demonstrates that the proposed method can help to uncover them.

5. Conclusions

This study sought to develop a methodological framework capable of identifying and differentiating anti- and crypto-Manichaean elements within Augustine’s Epistulae. It began by examining the epistolary corpus itself, foregrounding its value as a source for tracing Augustine’s post-conversion development and highlighting its communicative context as a locus of public dialogue and doctrinal engagement. The second section outlined two principal trajectories for interpreting Manichaean themes within the letters and emphasised the enduring relevance of Augustine’s formative years as an auditor in the sect. The third section proposed a concrete methodology for detecting Manichaean resonances, combining elements of phenomenology, hermeneutics, and close textual analysis. In addition to delineating a strategy for engaging with the Epistulae, this section underscored the necessity of dialogue with both authentic Manichaean texts and anti-Manichaean polemics. Finally, the methodology was put into practice through a detailed reading of Epistula 137, demonstrating how Manichaean concerns may have shaped the content and tone of letters without explicit reference to the sect.

The Epistulae, by virtue of their occasional nature and chronological breadth, offer a uniquely diachronic view of Augustine’s intellectual and theological maturation in the decades following his conversion. As documents largely unedited by Augustine himself, they preserve unmediated glimpses into his thinking at particular historical junctures: moments in which pastoral necessity, rhetorical exigency, and polemical urgency intersect. Unlike the carefully composed treatises, the letters often reflect the concrete immediacy of context-bound response, affording insight into theological positions still in formation. Within this framework, Augustine’s prolonged affiliation with Manichaeism, long undervalued in scholarship on his letters, emerges not as a marginal biographical detail but as a deeply formative influence. The nine years he spent within the sect, though as a mere auditor, coincided with critical stages of intellectual development and continued to shape his thought well beyond his formal break with Manichaean doctrine. His past surfaces in his vocabulary, in the adoption and subversion of Manichaean categories, and in the recurring need to clarify Catholic orthodoxy against Manichaean distortions. While his exposure may not have included the full range of Manichaean ritual and liturgical practice, Augustine nonetheless remains our most informative source on Manichaean ethics.

To retrieve these thematic currents from the Epistulae, this study proposed a methodological approach grounded in three interpretive pillars: phenomenological openness, hermeneutic precision, and close reading. The phenomenological dimension requires the interpreter to put aside theological assumptions and to encounter the text without preconceptions regarding orthodoxy or heresy. The hermeneutic component involves a conscious reframing of the letters to render latent Manichaean echoes perceptible, without distorting the integrity of the texts themselves. Once resonances are identified, they are subject to textual, linguistic, and doctrinal analysis, including attention to rhetorical strategies and biblical citations. Finally, close reading reveals submerged motifs and allusions that, while not dominant in the argument, are structurally embedded and contextually meaningful.

Crucially, the success of this method depends on sustained engagement with both Augustine’s anti-Manichaean treatises and genuine Manichaean sources. The Confessiones remain indispensable for reconstructing Augustine’s pre-conversion outlook, while his polemical works offer a systematic catalogue of doctrines he opposed. Genuine Manichaean writings, especially those in Greek, Coptic, and Syriac, provide invaluable access to the worldview and conceptual framework of the sect. Greek anti-Manichaean texts, which often quote Manichaean sources directly, further enrich this comparative enterprise, offering perspectives from Christian communities in the East who engaged with the sect prior to Augustine.

The application of this approach to Epistula 137, addressed to the non-Christian Volusianus around 411–412, yielded promising results. Though the letter refrains from naming Manichaeism explicitly, it contains sustained critiques of Manichaean Christology, couched in recognizably Manichaean terminology and distinguished sharply from Catholic doctrine. It also addresses, albeit obliquely, the sect’s characteristic materialism and Docetism. These thematic parallels are corroborated by extant Manichaean sources, while polemical texts such as the Acta Archelai and the writings of Titus of Bostra confirm that Augustine is engaging beliefs widely held by the sect. The choice to omit explicit references to Manichaeism may reflect strategic caution, perhaps in view of latent Manichaean sympathies in Carthage or among Volusianus’s associates. Augustine, cognisant of the sect’s proselytising habits, likely employed veiled polemic to neutralise its influence without exacerbating tensions or alienating his interlocutor.

In conclusion, this study aimed to reposition the Epistulae as vital sources for understanding Augustine’s theological development and rhetorical strategies in relation to Manichaeism. By tracing the enduring imprint of his Manichaean past in letters spanning four decades and by proposing a methodology sensitive to both historical context and textual nuance, it invites a re-evaluation of the epistolary corpus not merely as supplementary to the treatises but as a privileged locus for observing the negotiation of identity, orthodoxy, and memory in the long arc of Augustine’s intellectual life.