Achard of Saint-Victor is much less well-known than either Hugh or Richard of Saint-Victor. His literary output is not as wide-ranging as that of Hugh and Richard, and never attracted the same degree of attention from copyists. We do not know much about his life, other than that in 1155 he took over as abbot of Saint-Victor, but was soon sought out for his administrative skills, becoming bishop of Avranches between 1161 and his death in 1171. While his output is not large, it is slowly gathering attention. It includes a collection of sermons (edited by Jean Châtillon in 1970) and a treatise »De discretione animae, spiritus et mentis«, on the distinction between the soul, spirit and mind (although this was attributed to Gilbert of Poitiers by Nicholas Häring in 1960). Perhaps Achard’s most important composition, however, is his »De unitate et pluralitate creaturarum«. Fragments of its text were initially published in 1944 by André Combes through his discovery of quotations provided by Jean de Ripa, who attributed the work to St Anselm. The discovery by Marie-Thérèse d’Alverny of a complete text of the work in a manuscript of Padua (Biblioteca Antoniana, Scaff. V, 89), copied in 1352, made this hypothesis impossible to sustain. The treatise was re-edited as a composition of Achard of Saint-Victor by E. Martineau in 1987, while Hugh Feiss published an English translation of Achard’s writings with Cistercian Publications in 2001.

In this context the publication of a detailed study of the »De unitate et pluralitate creaturarum« by Iryna Lystopad can only be welcomed. She argues that it provides precious insight into what she sees as original Platonist philosophical reflection at Saint-Victor. This is important because it counters a widely held assumption that the focus of attention at this abbey was on theological and spiritual doctrine rather than on philosophy. In most accounts of twelfth-century thought, Platonist philosophy is associated with the school of Chartres, above all those disciples of Bernard of Chartres, namely Thierry of Chartres, William of Conches, and Gilbert of Poitiers. Lystopad puts forward a powerful case for assessing this treatise as important philosophically. In its analysis of the unity and plurality underpinning creation, Achard offers an original way of approaching not just the doctrine of the Trinity, but also Christology and other theological topics. It has long been observed that Hugh of Saint-Victor (under whom Achard certainly studied) was certainly shaped by Platonist philosophical assumptions – as with Hugh’s teaching in the »De tribus diebus« that the sensible world (mundus sensilis) was like a book revealing the attributes of divinity. Lystopad tends to steer away from larger generalities about Achard’s place in twelfth-century thought. Implicit in her argument, however, is a sense that just as Andrew and Richard of Saint-Victor each developed aspects of Hugh’s teaching (one on the historical interpretation of Scripture, the other on its mystical significance), Achard extended Platonist aspects of Hugh’s thought into a coherent system.

Lystopad organises her monograph in a systematic fashion. She begins by introducing what we know about Achard, the manuscript of Padua, and a detailed summary of its contents. This is followed by a second part, about unity and plurality in God, with much valuable comparison to the teachings of both Hugh and Richard about the Trinity, and finally a third part about plurality in the created world. There is a subtle issue raised by Achard’s title, in which »De unitate« was emended by Martineau who assumed that he was referring to the unity of God. In fact, Achard is using philosophical argument to arrive at Christian doctrine, precisely the same technique as pursued by St Anselm in his »Monologion«. While Jean de Ripa and Combes were clearly mistaken in thinking that St Anselm was its author, the possibility deserves consideration that Achard (whose background appears to be Anglo-Norman) was in part influenced by the method of St Anselm. Lystopad’s major focus, however, is on the Platonic notion of forms. She helps us see how indebted Achard is to the concerns of Bernard of Chartres, whose Platonism (famously dismissed by Richard Southern) provided fertile ground in the twelfth century for a number of different thinkers. Achard’s attention to different types of equality and similitude in God provides a way of identifying plurality in God quite differently from Peter Abelard, whose focus is on human predication of the divine rather than on forms independent of matter. Perhaps the most intriguing aspect of Lystopad’s analysis is her demonstration that Achard combines the influences of Augustine and Eriugena, to produce a synthesis of Platonist teaching that both draws on and transforms aspects of the ideas of two very different thinkers. For one reason or another, Achard does not seem to have been significantly influenced by the writings attributed to Denis the Areopagite. Rather he follows a line of thought prompted by Boethius (whose influence is just as important as that of Augustine) in using forms to provide a point of connection between the divine, divine attributes and the created world. Interpreting Boethius in a way that echoes, but is also distinct from both Gilbert and Thierry helps Achard to theorize that things exist both in intellectu and in actu.

A brief review cannot do justice to the finesse of Lystopad’s reading of the »De unitate et pluralitate«. Her analysis provokes further questions that deserve further resolution, in particular relating to Achard’s potential influence on Richard of Saint-Victor. It could well be that administrative responsibilities prevented Achard from developing his thought further. His sermons and the treatise on the powers of the soul still await further study. Nonetheless, Lystopad is to be commended for drawing attention to the originality of a less-well known member of the school of Saint-Victor. Her contribution to the »Bibliotheca Victorina« (no. 28 no less) makes an important contribution to both metaphysical and trinitarian thought in the twelfth century.