It is important to remember that until the late Middle Ages contemporaries did not regard “elective” and “hereditary” monarchies as sharply defined constitutional alternatives. Even English kingship contained elective elements in that the aristocracy’s consent was required for a succession to be legitimate, while hereditary rule in France was achieved in practice by many kings crowning their sons as successors during their own lifetime. . . .

The Empire got “the best of both worlds,” because its monarchy was theoretically elective but often hereditary in practice. Nobles and the population generally preferred sons to follow fathers as this was interpreted as a sign of divine grace. Of the 24 German kings between 800 and 1254, 22 came from four families, with sons following fathers 12 times.

The empire officially remained elective in form to the very end, but for all practical purposes, the crown became hereditary after the election of Habsburg Maximilian I in 1508. From then on, with the exception of a brief interregnum and short reign by a Bavarian rival in the 1740s, every remaining emperor would be a Habsburg. As a result, imperial interests would sometimes be subordinated to those of the growing territories outside the empire that were part of the Habsburgs’ ancestral domains, ultimately embracing large chunks of Poland, Ukraine, Slovenia, Croatia and the Venetian Republic, to mention just a few. As Edward Crankshaw put it in The Hapsburgs: Portrait of a Dynasty,

The revival of the Roman Empire, created by Charlemagne as part of his dream of uniting all Christendom under one temporal head, and to become known as the Holy Roman Empire, had long ceased to mean much in terms of power. But the Emperor was still vested with a quasi-mystical authority, even though he was now little more than an elected figurehead, or King, of the German peoples.

All of which has contributed to the dismissive attitude of most modern historians writing during or after the empire’s decline and ultimate dissolution. “The Empire’s demise coincided with the emergence of modern nationalism as a popular phenomenon,” Wilson writes,

as well as the establishment of western historical method, institutionalized by professionals like Leopold von Ranke who held publicly funded university posts. Their task was to record their national story, and to shape it they constructed linear narratives based around the centralization of political power or their people’s emancipation from foreign domination. The Empire had no place in a world where every nation was supposed to have its own state. Its history was reduced to that of medieval Germany, and in many ways the Empire’s greatest posthumous influence lay in how criticism of its structures created the discipline of modern history.

. . . For many, especially Protestant writers, the Austrian Hapsburgs wasted their chance once they obtained the imperial title . . . [by] pursuing the dream of a transnational empire rather than a strong German state. . . .

The Empire took the blame for Germany being a “delayed nation,” receiving only the “consolation prize” of becoming a cultural nation during the eighteenth century, before Prussian-led unification finally made it a political one in 1871. . . . Only after two world wars had discredited the earlier celebration of militarized nation states did a more positive historical reception of the Empire emerge.

AND THEN there is the question of what exactly makes an empire an empire. The year following Hitler’s annexation of Austria and acquisition of the imperial regalia, the Nazi high command ordered all official organizations to stop referring to the regime as the “Third Reich.” In effect, the Nazis were declaring the First Reich a nonempire on the grounds that it was too holy, too Roman and not German enough by half. Ergo, it wasn’t really an empire at all—a grotesque but logical extension of von Ranke’s less rabid critique at an earlier, less brutal phase of German nationalism.

Wilson makes a reasoned and convincing counter case. He suggests three basic yardsticks for evaluating an empire: size, longevity and hegemony. The least useful of these, he argues, is size. “Canada,” he points out,

covers nearly 10 million square kilometres, over 4 million square kilometres larger than either the ancient Persian empire or that of Alexander the Great, yet few would contend that it is an imperial state. Emperors and their subjects have generally lacked the obsession of social scientists with quantification; on the contrary, a more meaningful defining characteristic of empire would be its absolute refusal to define limits to either its physical extent or its power pretensions.

There is something more to be said for the second element, longevity. Historical significance of an empire depends on its passing

the “Augustan threshold”—a term derived from Emperor Augustus’s transformation of the Roman republic into a stable imperium. This approach has the merit of . . . identifying why some empires outlived their founders, but it should be recognized that many which did not nonetheless left important legacies, such as those of Alexander and Napoleon.

Hegemony is the third element and perhaps the most ideologically charged. Some influential discussions of empire reduce it to the dominance of a single people over others. Depending on perspective, the history of empire becomes a story of conquest or resistance. Empires bring oppression and exploitation, while resistance is usually equated with national self-determination and democracy. This approach certainly makes sense in some contexts. However, it often fails to explain how empires expand and endure, especially when these processes are at least partially peaceful.

For all of its many failings, the Holy Roman Empire encompassed a large territory that was also prime real estate at the time; lasted over a thousand years, which qualifies as longevity by any reasonable imperial standard; and maintained a comparatively peaceful and benevolent “hegemony” over a region that made impressive developmental strides economically and culturally long before the modern concept of nationalism and the nation-state even existed.

Even at its weakest, the empire provided a unified postal service and other useful institutions plus a judicial framework for mediating and settling disputes that could otherwise have led to violent conflict within and between its member entities. Its very weakness—the limits on its practical authority as the paramount power within a federation of principalities—led to long periods of peace within the empire in much the same way that large and small fish of different species can coexist in a carefully balanced aquarium. In this respect, the empire was prenational and postnational, the harbinger of later and, in some cases, ongoing attempts to create benevolent, voluntary structures that overarch national boundaries, such as the British Commonwealth, the Organization of American States and the European Union.

In this context, the empire’s weakness can almost be viewed as a strength, a structure based on shared values and traditions that served a positive purpose without imposing an authoritarian central power on diverse member states and peoples. This was a tradition carried on by the Habsburgs in their sprawling domains after the demise of the Holy Roman Empire.

WHAT BEGAN in the year 800 with the crowning of one warrior ruler, Charlemagne, as an emperor ended, for all intents and purposes, in 1804. In that year, another brilliant but rough-edged conqueror, Napoleon Bonaparte, in the presence of Pope Pius VII, crowned himself “Emperor of the French.” In doing so, he invoked the spirit of the thoroughly Germanic Charlemagne as a dubious precedent. Even the crown used at Napoleon’s coronation, a hastily improvised stage prop in pseudoantiquarian style, was spuriously dubbed “The Crown of Charlemagne.” The Holy Roman Empire managed to limp along until 1806, but the handwriting was on the wall. Revolutionary France had already annexed the Austrian Netherlands and western German states. Having assumed the imperial purple himself, Napoleon would soon create a series of German satellite states, further undercutting what remained of the Holy Roman Empire. Emperor Francis II, its last ruler, saw it coming and, possibly anticipating a Napoleonic attempt to supplant him on the true throne of Charlemagne, created a new fallback position for himself. Already the Habsburg King of Hungary and Archduke of Austria, he elevated his Austrian title to “Emperor.” When Austria suffered a humiliating defeat at the Battle of Austerlitz—and some of the most powerful princes within the Holy Roman Empire, most notably Bavaria and Württemberg, had allied themselves with Napoleon—Francis abdicated as Holy Roman Emperor, and patiently waited to fight another day. As Edward Crankshaw put it,

[Francis’s] gentleness in the family circle, his lethargy, his refusal to fuss, his celebrated lack of pretentiousness, his habitual projection of an amiable, easy-going cynicism, provided not so much a protective shield as a convenient camouflage for one of the toughest and most determined figures in Hapsburg history. He would cut his losses with a display of equanimity that at times seemed frivolous. But he knew what he was doing, and why. And he never confused shadow with substance. Thus when, in 1806, after the Treaty of Pressburg, the Holy Roman Empire was solemnly abolished under pressure from Napoleon, Francis blandly laid down the Imperial crown, which was never to be worn again. But two years before, seeing the way the wind was blowing, he had given himself a new Imperial style and had himself proclaimed Emperor of Austria, and it was thus as His Imperial and Apostolic Majesty, Emperor of Austria, King of Hungary, that he survived Napoleon’s fall and, as the senior monarch, welcomed the majesties and highnesses of Europe to the Congress of Vienna.