This is a doctoral dissertation, only lightly reworked as is normal at German universities, where there is an obligation to publish PhD theses without delay. The best of them are accepted for publication in academic series. There is no better German series than the Schriften der Monumenta Germaniae Historica, so one’s a priori expectations are positive. They are not disappointed: this is an important contribution to research. The intersection of sixth-century Christology and canon law is not everybody’s idea of a gripping read, but this reviewer found it so.

As the title suggests, the book brings together two strands in the history of religious thought more often studied apart: debates about the nature of Christ, and early medieval canon law collections. The latter have been well mapped, above all by Friedrich Maassen, whose research remains indispensable a century and a half after his Geschichte der Quellen und der Literatur des canonischen Rechts im Abendlande (Graz 1870) was published. His pioneer research has continued by Gaudemet, Jasper, Kéry and others. This fine work has been for the most part descriptive rather than interpretative. It has not overlapped much with the work of patristic scholars like Adolf-Martin Ritter, for instance.¹ Eber joins the wires so that a current of real intellectual excitement runs through them. His method is to read off the theological message of individual canon law collections by looking at the selection of texts, including texts not conventionally categorised as canon law. His principal finding is that churchmen in sixth-century Gaul understood much more, and agreed much less, about the Christological issues than scholars have hitherto supposed.

The core Christological issue was the relation of the human and the divine in Jesus. It was and is a central issue in Christianity and anyone who fails to understand why early medieval people were exercised about it should probably stay away from religious history. The remarkable thing is not that they cared and argued about it, but that the solutions reached before the Carolingian parting of ways between West and East have received such general assent from the Catholics, the Orthodox, and mainstream Protestants in subsequent centuries. The consensus was the outcome of hard-fought battles between those who emphasized the distinctiveness of the divine and human natures of Christ, those who emphasized the absorption of his humanity into his divinity, and those who tried to synthesize, in one way or another, the two positions. The Three-Chapter dispute which is at the centre of Eber’s book was really between two ways of reconciling the emphasis on distinctiveness and the emphasis on transcendent divinity. The two ways look quite similar at least from a distance and understanding is further hampered by the fact that we are dealing with condemnations of a condemnation. Double negatives are never so easy to absorb. Eber does a good job of untangling the issues.

There was a political background to the dispute. The formula of the Council of Chalcedon – one person, two natures – left many in the Byzantine empire unhappy. These were the »Monophysites« or »Miaphysites« (the difference has never been clear to this reviewer). The emperor Justinian wanted to appease them and keep the empire united by promulgating an approach that they found less offensive because it emphasized the unity of Christ. His way of doing so was to condemn the writings (the famous Three Chapters) of three theologians who allegedly emphasized too much the separation of the two natures.

Justinian was neither the first nor the last Eastern emperor to try to draw »one nature« believers back in to the fold by going some way to meet their views. As both before and afterwards there was a rocky response in the West, and as in the Monothelite dispute in the following century, the emperor wanted to get the pope on his side and was prepared to use force to do so. Justinian used his overwhelming power against pope Virgilius (537–555) and his aide and successor Pelagius I (556–561), who eventually endorsed the condemnation of the Three Chapters, though they tried to play down their changes of mind. That gave rise to a schism in the province of Aquileia, and to a reaction also in Gaul, though it is Eber’s argument that there was a spectrum of opinion about it all there.

Previous scholarship on the reception of the dispute in Gaul has relied primarily on a letter of Nicetius of Trier, and interpreted it as him being very confused about the whole theological problem. Eber argues that Nicetius was not confused, but, rather, advocating a middle way. In any case, too much interpretation has rested on this letter, according to Eber, who argues that opinion in Gaul was quite divided, which would explain why there was an intermission in the tradition of Pan-Frankish synods after the Council of Orléans in 549.

First the attitudes of Gallic bishops before 549 are elucidated. The key background is the difference between »Leonine« and »Neo-Chalcedonian« Christology, shorthand for emphasis on the difference of the natures and the unity of the person respectively. An unexpected intersection, from the reviewer's perspective, exists between that debate and the historical controversy about grace and free will that goes back to Pelagius and Augustine. There appears to have been a perceived affinity between the Augustinian attitude to grace and Neo-Chalcedonian Christology. Eber shows that the latter was understood in Gaul even before the Three-Chapter controversy and that the spectrum of sophisticated opinion in Gaul in the second decade of the sixth century was wide, and included views potentially sympathetic to the condemnation of the Three Chapters.

The heart of the book however is an analysis of three manuscripts whose respective contents reflect different attitudes to the Three‑Chapter dispute. He uses the names given to them by Maassen, while making it clear that these do not tell one where the canon law collection in question originated. Eber speculates plausibly that the collections were put together to provide evidence to convince councils. The collections establish »vertical consensus«: texts showing that the particular Christological view propounded had deep roots in tradition.

Against this background a variety of reactions in Gaul to the Three‑Chapter dispute should no longer surprise us. Eber brings out the variety by applying the »method of associated content« of manuscripts which has been developed over the last half century or so: the selection of texts in a manuscript tells a historical story. So does the fluid history of a canon law collection across the different redactions that transmit it in different manuscripts. In this case, they represent attitudes to the Three-Chapter dispute. The Collectio Remensis is hostile to the condemnation of the Three Chapters and to Justinian. Conversely, the Collectio sancti Mauri is strongly pro-papal. Finally, the Collectio Coloniensis is »Neo‑Chalcedonian« – favourable to Justinian’s condemnation of the Three Chapters. It is an important finding of the book that Gallic bishops were not unanimously opposed to Justinian’s »Neo‑Chalcedonianism«, an implication of which is that their later reconciliation with it was not solely due to papal persuasion (after pope Pelagius I had abandoned his original opposition). Nonetheless Eber’s findings show a Gaul closer in one way or another to the papacy, despite the Three-Chapter dispute, than I at least had previously believed it to be.

The manuscript analyses underlying this argument for three quite different ways of dealing with the controversy are dense and complex and this reviewer cannot pretend to have assimilated all the details, but the general thrust of the thesis carries conviction. The book deserved the distinction of inclusion in this important series. It certainly shows a side of life and thought in sixth-century Gaul quite different from the image one takes away from the Histories of Gregory of Tours.