Say “the Holy Roman Empire” and you are likely to get one of four responses.

The person you are speaking to thinks you are talking about the Roman Catholic Church.

The person thinks you mean the Roman Empire.

You get the knee-jerk reply, “It wasn’t holy, Roman, nor an empire,” the person most likely unaware that they are quoting French Enlightenment philosopher Voltaire.

You get a blank stare.

The Holy Roman Empire is arguably the best kept out-in-the-open secret of pre-modern European history. Located at the center of the European continent, it was a dominating force in European politics, religion, and warfare for nearly one thousand years.

It was in the Holy Roman Empire that the Roman Catholic Church faced its first major secular opposition through the Investiture Controversy. It was in the Holy Roman Empire that Martin Luther published his 95 Theses. It was in the Holy Roman Empire that Protestantism as a third branch of Christianity developed. It was because of decisions made in the Holy Roman Empire that Spain became an Empire in and of itself. The Holy Roman Empire is where the Thirty Years War, the most destructive military conflict on the European continent, second only to World War II, was fought. The Thirty Years War ended in 1648 with the Peace of Westphalia, negotiated and signed in the Holy Roman Empire, and which continues to influence international politics to this day. The Holy Roman Empire is the First Reich to Adolf Hitler’s Third.

And still so few have heard of it.

One reason for the obscurity of the Holy Roman Empire could be that it is notoriously difficult to define. Starting with when the Empire existed, there is consensus that it ended in 1806 when it was dissolved to prevent Napoleon Bonaparte from getting his hands on the Imperial title. But when did it begin? Some scholars say with Charlemagne (9th century), some with Otto I (10th century). When did the Empire get its name? No one really knows. What is the Empire’s name? Well, that depends.

Another reason for the Empire’s obscurity could be that the vocabulary we use today to explain geopolitical territories lacks the words to describe what the Empire was. In one way, Voltaire was right; the Holy Roman Empire was not holy, not Roman, and not an Empire. Granted, there was an Emperor who ruled over it, which by definition makes it an Empire. Furthermore, this Emperor claimed to be the successor of the Emperors of the actual Roman Empire. But when the Holy Roman Empire came into existence, Rome had been gone from the European continent for more than three hundred years.

Moreover, the territory the Holy Roman Emperor ruled consisted of a plethora of political and judicial entities–secular and clerical, alike–who all had a different relationship to the Emperor as a person and as a sovereign. To complicate matters further, the Emperor didn’t inherit his position; he was elected by an Electoral College. Whom these Electors elected depended as much on politics and alliances as it did on pedigree. The extent of the lands that the Emperor ruled depended on the person, meaning that depending on the martial prowess of the medieval Emperors or the family ties of the early-modern Emperors, the Holy Roman Empire stretched and contracted based on who was elected Emperor.

To avoid having to get into the intricacies of the Holy Roman Empire at any given time when discussing medieval and early-modern European history, “Germany” has become sort of a short-hand, which in one way is correct because the Empire did cover much of what is Germany today, and over time, it became formally known as the Holy Roman Empire of the German Nation. But it is also incorrect because the Holy Roman Empire included parts of what is today Austria, France, BeNeLux, Poland, the Czech Republic, and Italy.

Swedish historian Harald Gustafsson perhaps says it best when he describes the Holy Roman Empire as “a complicated entity that floated around the map of Central Europe for a thousand years.” (my transl.)

In an attempt to make sense of this complicated thing that floated around on a map and claimed to be something it was not, historian Peter H. Wilson wrote his book Heart of Europe (Belknap Press of Harvard University Press, 2020). Similar to the subject it tackles, the book is a colossus, clocking in on 1,008 pages (one page for each year the Empire existed?).

Instead of tracing the Empire’s history chronologically, Wilson comes at it thematically. Each chapter deals with one aspect of the Empire’s complicated existence. Still, the internal structure of each chapter is chronological so that once you get to the end of the book, you also get to the end of the Empire.

The thematic structure works well because it enables the reader to pick and choose what to read and delve deeper into. It also works well because where most histories of the Empire focus on its early-modern history, this approach gives ample room to discuss the Empire’s medieval history, without which the developments of the early-modern period would be difficult to understand (e.g., the explosiveness of the Reformation can only be fully understood if you are aware of the severity and the repercussions of the Investiture Controversy).

The problem with the thematic structure is that it becomes difficult to locate where specific turning points in the history of the Empire are explained. Same thing with terms of art, which in the case of the Empire’s government bureaucracy are numerous and often in German. The book contains a glossary and an index, but the glossary is quite short and the index quite long, which results in neither of them being particularly helpful. There is a chronology, but because the Empire existed for as long as it did, the chronology is 55 pages long and still only skims the surface.

The book contains several maps that chart the development of the Empire from its beginnings to its end, and present some of the many Leagues that formed as a result of shifting political, religious, and dynastic alliances over the centuries. The maps are detailed and meticulous, and provide a welcome visual aspect to the complicated internal structure of the Empire. Also included are the family trees of the most significant family groups and dynasties that dominated the position of Emperor in the Middle Ages and the Early-Modern Period.

Peter H. Wilson’s Heart of Europe is a much-needed deep dive into the complicated history of the Holy Roman Empire, the knowledge of which is crucial to the understanding of European history, from the Middle Ages until today.

In the words of my friend, the Australian, I shall return.