One reason for the patchiness of our understanding of the Holy Roman Empire is that it had hardly any direct impact on Britain and relatively little on France – though Proust’s narrator goes to sleep dreaming of la rivalité de François Ie et de Charles Quint – and first really forces itself on our attention when we study the history of Italy in the medieval and early modern periods. Most of all it was a central European phenomenon, concerning the German-speaking peoples as well as the Czechs, Hungarians, and some other subject nations.

A further reason why even educated people have a vague grasp of the subject is that there was something inherently vague about the Empire itself. It was not a nation, but something more like a federation; it had a system of elective monarchy – hence the Electors – and the emperors, with limited financial resources, were only occasionally in a position to project their military power beyond their own territories. And yet, in medieval political theory, papacy and Empire were the two divinely ordained pillars of the Christian world: ultimately, the Empire guaranteed the security of the Church in the temporal realm, while the Church endorsed the emperor as a figure of quasi-sacred authority in the secular domain.

As Peter H. Wilson argues in this admirable new history of the subject, even academic study of the Empire suffered, over the last century and a half, from the nationalist bias of mainstream, originally nineteenth-century history, with its belief in the self-determination of peoples and its idealisation of the unifications of Italy (1860) and Germany (1870) as triumphs of the modern and progressive state. In such a teleological perspective, the Empire tended to be seen as an early but misconceived and ultimately abortive attempt to unite the German peoples into a nation-state.

Charlemagne accepts Widukind's submission in Paderborn, 1835, oil on canvas (Ary Scheffer [1795–1858], Wikimedia Commons)

Today, more than half a century after the crash-and-burn end of militant German nationalism, and surrounded by recent examples of the savagery of newly-freed and would-be self-determining ethnic and religious groups – from the breakup of Yugoslavia to the meltdown of the Arab dictatorships – we are less inclined to equate nationalism with progress. The story of a massive and multi-ethnic political association that survived so many turbulent centuries no longer looks like one of stagnation and missed opportunities, and may even offer lessons for the evolving European Union; unfortunately, this volume was probably not on the bedside tables of those who voted for Brexit a few months ago.

Particularly interesting in this regard is the way that the Empire, in spite of its special relationship with the papacy, took the Reformation in its stride. By this time the imperial crown had effectively become hereditary within a single family, the Austrian Hapsburgs, whose own vast landholdings, both within and outside the boundaries of the Empire, provided them with economic and political power in their own right. The Hapsburgs always remained Catholic, but they were not in a position to suppress the German princes who adopted the cause of the Reformation, and in the end the system allowed for co-existence between Catholic and Protestant states within a Christian Empire. That is why, when the Huguenots were expelled by Louis XIV after 1685, many could find refuge within the imperial territories.

The case of the Jews is also instructive: they were placed under the direct protection of the emperor, which meant, as Wilson points out, that enforcing their security became a matter of law and order, and of maintaining the prestige of the state. In the anti-Jewish hysteria that flared up periodically, there were indeed from time to time massacres and expulsions, but these were regularly punished and reversed, respectively, and in an increasingly effective manner after new laws were enacted in the sixteenth century.

Peter H. Wilson (photograph by Justine Stoddart)Wilson’s book is arranged thematically rather than chronologically: it has four main parts, under the headings ‘Ideal’, ‘Belonging’, ‘Governance’, and ‘Society’. Each of these is in turn divided into three chapters – thus ‘Society’ comprises ‘Authority’, ‘Association’, and ‘Justice’ – creating an overall duodecimal structure that is implicitly in harmony with the medieval origins of the institution itself. If one needs to check the year-by-year sequence of events, these are outlined in a separate fifty-page chronology. There is also an extensive glossary, as well as lists of the reigns of the kings and emperors who ruled over the Empire through the centuries, as well as exhaustive notes citing all bibliographical sources, and an index.

The scholarly achievement is massive, the sheer quantity of material mastered in producing this history daunting; and yet for all its size and weight, Wilson’s book is highly readable. One reason for this is no doubt his thematic structure, which allows us to follow the story of particular topics, such as the Reformation and religious tolerance, or the Empire’s characteristically corporate and consensual political institutions, so different from the ‘modern’ model of absolute monarchy. But it is also a credit to Wilson’s writing that his style is clear and penetrating, infectiously conveying the author’s own evident fascination with a subject that turns out, as he rightly asserts, to lie at the heart of the European experience.