This is a ‘book of the thesis’ but much longer than its counterparts in the British system, where theses have a draconian word-limit. Massetti’s book weighs in at 759 pages. In principle all German dissertations must be published in some form (another contrast with the Anglophone world), but the best and luckiest ones get accepted, presumably with a subsidy, in a good series like this one, which is edited by two leaders in the field of papal history, one of them Massetti’s Doktorvater and mentor Jochen Johrendt, who has built up an international school. The intended readership does not include the non-Latinate, as quotations are left untranslated. It is true that it is still normal for Humanities students in Germany to pass a Latinum test, grosses or kleines – so some keen German students will be able to use it. But it is mainly for scholars. For Anglophone students and even scholars a substantial review may be useful.

The aim of the volume is to present with a wealth of generous detail the role of Leo ix, Bruno of Toul, in the eleventh-century ‘papal turn’, a phrase which has partly replaced ‘Gregorian Reform’. The last phrase has the disadvantage of implying that the big changes began with Gregory vii. The whole movement has of course been much studied, but Massetti’s book is more thorough than anything previously written on Leo ix. It is based on a near-comprehensive familiarity with both primary sources and scholarly literature. The bibliography runs to some ninety pages. The main parts of the book deal respectively with ideas and action, in that order.

The papal turn owed much to the theological ideas of Leo ix, according to Massetti, who argues that he developed significantly the existing ideology of papal primacy. He does not develop the contrast with earlier papal ideas, except with the ‘Gelasian doctrine’, a debatable contrast. (Papal ideology had been well-developed long before: one could argue that it is the whirlwind embodiment of them in pro-active interventions that was really transformational. But the book is long enough without detailed comparison with predecessors like Nicholas i or Innocent i.) The unity of the Church is contrasted with the divisions that go with heresy. The papal office is sharply distinguished from the person who holds it. Papal authority is not just doctrinal but includes jurisdiction. The Pseudo-Isidorian decretals are pressed into service.

There is an interesting discussion of letters replying to African bishops, evidence incidentally of the survival of a Church through centuries of Islamic rule which retained memories of papal authority in late antiquity. Two bishops appealed to the pope because another bishop had usurped the authority of the archbishop of Carthage by deposing or consecrating one or more bishops and summoning a synod. Leo acceded to their request and took the opportunity to lay out the papacy’s claims as head of the Church by divine authority.

Massetti gives a fuller account of Leo’s ecclesiology in his discussion of a Libellus written in reply to a Greek text, addressed to ‘all the bishops of the Franks’ and to the pope, attacking Western liturgical practices. The Greek text used to be ascribed to the Patriarch Cerularius, but Massetti follows recent scholarship in rejecting the attribution. Massetti also rejects the attribution by Anton Michel of Leo ix’s reply, the Libellus, to Humbert of Silva Candida. That means he can use it as evidence of the pope’s own ideology, even though the Libellus was apparently never dispatched. Massetti attaches great significance to the Libellus as the first papal use of the Constitutum Constantini/Donation of Constantine as proof of papal temporal authority.

After the long discussion of Leo’s ecclesiology Massetti goes backwards in time to trace the future pope’s career in the imperial Church. It was a typical elite career. He was noble in origin, served in the royal chapel and proved himself as a diplomat. He owed his promotion to bishop to both pope and emperor. Massetti discusses the story that Bruno had made the consent of the clergy and people of Rome a condition. This has been questioned as a back-projection of later values, but Massetti thinks it might well be true.

The following chapter is on his relations with the imperial Church. His time as an imperial bishop influenced papal diplomatic: it explains the turning of the pope’s name and the Benevalete sign into a monogram. (His pontificate is a decisive break in papal documentary practice.) For two years he remained a part of it as he kept the bishopric of Toul. He granted the archbishop of Trier primacy over Gallia Belgica, and the right to wear the Roman mitra on feast days (ritual privileges mattered for status). As for Cologne, in addition to the usual ritual privileges Leo made the archbishop arch-chancellor of the Roman Church and gave him the church of S. Giovanni a Porta Latina as a residence in Rome. He granted him the right to anoint kings in his ecclesiastical province. Mainz too received symbolic ritual privileges, but these may have been a consolation prize for not renewing the primatial privilege granted by pope Benedict vii in 975. As just noted, Mainz lost to Cologne its privilege of anointing the king.

There is a long chapter on Leo’s synods. Roman synods were held much more frequently by Leo than in the past. His second synod (in 1050), for which we have a list of participants, was very international: there were bishops from Burgundy, France, England and France, and also from Southern Italy. Only one member of the imperial Church attended. Simony was high on the agenda. Other matters addressed were the recovery of church lands, marriage within the forbidden degrees, questions of primacy within ecclesiastical provinces, canonisations and the eucharistic doctrine of Berengar of Tours.

Leo held the first synod in France since 878, and despite opposition from the French king. He also held a synod at Mainz, together with the emperor Henry iii. The chapter gives an overview of all the synods, and argues that they marked a turning point, as they established the papacy as the leader of a reform movement.

The final full chapter is on Leo’s journeys. He was a tireless traveller: never in Rome for more than three months at a time and only nine months there in toto. His travels were modelled on episcopal visitations (here Massetti follows Johrendt). In the course of them he consecrated many churches, altars and cemeteries. Massetti unpacks the meanings of these consecrations in pages of illuminating ‘thick description’. Leo also presided over canonisations of the traditional sort: raising and translation of the saint’s relics. This is a far cry from papal canonisation as it would develop, especially under Innocent iii, but it was still an assertion of papal authority, because Leo was taking on the role that would otherwise be performed by the local bishop. A special case is the journeys to Southern Italy, where Leo tried, unsuccessfully, to strengthen the papacy’s political position vis à vis Normans, Saracens and Byzantines.

This takes one back to the Donation of Constantine. I would tentatively suggest that Leo’s use of it in the Libellus (if he is the author) makes the most sense in the context of legitimising papal political claims in Southern Italy, rather than as pure ecclesiological ideology. It makes sense that Leo would want to find an ideological underpinning for his efforts to keep a political power base in the South.Footnote ¹

In purely ecclesiological terms the Donation was very subversive of papal claims, suggesting as it did that papal authority depended on a gift from a Roman emperor. Daniel Edwin Dominic Müller has argued this point powerfully: ‘The logic of the Constitutum always reminds [sic] of the imperial source of any papal power and with that creates an ominous dependency of the popes on the emperor.’Footnote ² Massetti is well aware of this and correctly interprets the Libellus but he needs to be read carefully to avoid misunderstanding. The key sentence can be unpacked as follows: God gave spiritual power to the pope, and secular power to the emperor, who in the Donation gives the secular power (in the West only) to the pope; he is ‘giving it back’ to God in his servants, but they did not have this secular power before.Footnote ³

Only with regard to secular power in Italy could this be of any real use to the papacy. North of the Alps, where it had no political power to speak of, it undermined papal claims, for anyone who thought about it. So it is not surprising that, as Müller found, ‘the Constitutum was never publicly used to reinforce papal authority in the conflict with the German king’ in this period (in the thirteenth century Gregory ix would use it to undermine Frederick ii’s claims to authority in Italy); again: ‘although a noticeable increase in references to it was observable during the eleventh century and despite being contained in the flourishing genre of canonistic codices, the application of the forgery … fell short of what reasonably should have been expected of a document as promising as the Constitutum’.

So perhaps we should not overstate the influence of Leo ix in this particular respect. At any rate there is room for debate: I would suggest that it was his deeds that changed history, more than his words, and Massetti’s book gives as full an account of the deeds as one could wish for. There is no doubt that Leo ix was one of the most influential popes in the history of the papacy, and he has found a worthy biographer in Francesco Massetti.