For half a century after the death of Hilary of Poitiers in 367, Roman Gaul was a theological backwater deserving mention in the annals of Dogmengeschichte only because of the activities of the Spaniard Priscillian. As in the past, the decisive church councils took place elsewhere. So did most of the new Latin ecclesiastical writing that would prove formative for later tradition, be it now from the pen of an Ambrose, Jerome, ‘Ambrosiaster’, Pelagius, Rufinus or Augustine. The boutique operations of the well-to-do Aquitanian layman Sulpicius Severus and his celebrity friend Paulinus, expatriated at Nola, would count at best as partial exceptions to the general rule, attesting as they do the strength of the Gallo-Roman rhetorical tradition and the reliance of the province's resident Christian activists on initiatives taken abroad. But then, in the space of barely a decade and a half from the final condemnation of Pelagius in 418, this settled pattern of slightly précieux Gallo-Roman intellectual receptivity was transformed into a matrix for collaborative theological and exegetical production of a kind not seen before in any Latinophone milieu. How much of the change may have been due to a sudden influx of highly literate refugees to the Côte d'Azur and lower Rhone Valley from other parts of the province is still debated by scholars. What is clear beyond doubt is that the establishment of monastic communities at Marseille and Lérins encouraged new styles of intellectual and literary sociality, one measure of which would be the bibliography of Gallo-Roman authors from between 420 and 470 that forms the backbone of the catalogue De scriptoribus ecclesiasticis compiled by Gennadius as a sequel to Jerome's work of the same title. At the beginning of this distinctively Gallican movement in Latin literary history stand Prosper of Aquitaine's prosimetric recasting of the doctrinal oeuvre of Augustine, the patristic argumentation of John Cassian's De incarnatione contra Nestorium, the theory-in-practice embodied by the Commonitorium (or Tractatus Peregrini) and Excerpta of Vincent of Lérins, and the writings of Eucherius, another monk of Lérins (now Ile St-Honorat, near Cannes), who was consecrated bishop of Lyon sometime between 435 and 439.

As the most accessible member of the company gathered by Salvatore Pricoco in L'isola dei santi (1978), Eucherius has enjoyed ever closer study in recent years. Martine Dulaey's introduction to this volume gives a concise but full account of the state of scholarship. The two biblical-exegetical works that she presents, namely (in the order in which they appear here and in the manuscript tradition, probably reversing the order of composition) the Formulae spiritalis intellegentiae and Instructionum libri duo, compiled between 430 and 434, have been available since 2004 in an edition for CCSL by Carmela Mandolfo which improved significantly on that of Karl Wotke in CSEL and is the basis for this one. The generous mise en page of the SC edition – the first to include in-text authorial chapter-headings for the Formulae – makes it now the best place to consult these texts. Both works, Dulaey explains, were instruments de travail, aids to personal study (pp. 33, 51) for persons already well versed in the Scriptures and willing to do the necessary work (pp. 36, 49). Book i of the Instructiones offers solutions to miscellaneous problems of interpretation from Genesis to Revelation, while Book ii serves as ‘a dictionary of the realia of the Bible’ (p. 19), its 396 entries covering Greek and Hebrew names, names of peoples and persons, place names and the like. Complementing the Instructiones, the Formulae constitutes ‘a dictionary of symbols, intended to elucidate the figurative sense of the Scriptures’ (p. 30), its 458 entries arranged under such headings as ‘Animals’, ‘Things in common use’, ‘Jerusalem and her adversaries’ and ‘Numbers’. Originally addressed to the author's sons while he and they were living on Lérins or the neighbouring island of Lero (now Ste-Marguerite), these opuscula were put into wider circulation as a package once Eucherius became bishop (pp. 16–18, 50–1). The special value of Dulaey's edition – a tour de force of its kind, exemplifying a style of French patristic scholarship that we have grown used to seeing almost explode the handy SC format – lies in its comprehensive reporting of the sources and analogues of the exegetical information provided by Eucherius. Jerome and Augustine are the dominant presences, alongside Cassian, whom Dulaey discovers her author ‘correcting’ on key points in an Augustinian (but not predestinarian) sense (pp. 47, 52–4). The overall range of Eucherian patristic reference is much wider than that, however (pp. 54–9). Lérins in the late 420s and early 430s was a patristico-biblical textual laboratory. Works like these helped canalise the headwaters of Latin biblical exegesis in ways that two of the founders of SC, Henri de Lubac and Jean Daniélou, may already have intuited but that are only now coming fully to light (pp. 59–61). ‘With Eucherius’, proclaims the back cover of SC dxviii, ‘a major author of Christian antiquity makes his entry in the collection.’ He does so with panache.