By Philip Daileader, William & Mary
On December 25, Christmas Day, 800, Charlemagne, Pope Leo III, and many others attended services at St. Peter’s Basilica, and during those services, Leo crowned Charlemagne and proclaimed him emperor. Whose idea was it to have the pope crown Charlemagne as emperor? In his Life of Charlemagne, Charlemagne’s biographer Einhard suggests that the coronation was the pope’s idea, and that it caught Charlemagne by surprise.

The Big Surprise
According to Einhard, “Charlemagne received the title of emperor and augustus, which at first he disliked so much that he stated that, if he had known in advance of the pope’s plan, he would not have entered the church that day, even though it was a great feast day.
Those who take Einhard at face value sometimes suggest that Leo crowned Charlemagne as emperor in a bid to regain control of events and to lessen his dependence on Charlemagne, whose imperial title depended on papal action.
In practice, though, the imperial coronation did not reset the pope’s relationship with Charlemagne—as emperor, Charlemagne remained the dominant figure. Leo, like Hadrian before him, looked to maintain a modest autonomy, where he could.
Diplomatic Conflict
In saying that Charlemagne had no idea that he was going to be crowned emperor, Charlemagne’s biographer may simply have been expressing conventional modesty. It would have been most unseemly for Charlemagne to state after the coronation that he had really, really wanted to be an emperor.

And there are other reasons for rejecting the claim that Charlemagne knew nothing beforehand about the coronation. To the claim of Charlemagne’s ignorance, Einhard adds the following: “But he bore the animosity that the assumption of this title caused with great patience, for the Roman emperors were angry over it.”
Those whom Einhard called “Roman” emperors, we would call Byzantine emperors. That Einhard segues immediately from Charlemagne’s expression of regret to the Byzantines’ animosity suggests why Charlemagne might have later wanted to disavow foreknowledge of the imperial coronation.
Charlemagne’s assumption of the imperial title fueled diplomatic conflict, and even a prolonged and not very successful war with the Byzantine Empire. In calling himself emperor, Charlemagne asserted his equality with the Byzantine emperors, which the Byzantines would not willingly countenance.
Charlemagne’s New Imperial Title
The awkward ramifications of Charlemagne’s imperial coronation for Frankish-Byzantine relations also help to explain the awkwardness of Charlemagne’s new imperial title: Charlemagne was not only king of the Franks and king of the Lombards, he was also “the crowned-by-God emperor ruling over the Roman Empire”.
Why not just Emperor of the Romans? Probably because the Byzantine Emperor used the title Emperor of the Romans; if Charlemagne had called himself Emperor of the Romans, he would have been issuing a direct threat against the Byzantine Empire and laying claim to it.
To sum up the vexed issue of the imperial coronation: almost certainly, Charlemagne must have known beforehand that he would be crowned emperor on Christmas Day 800. But Einhard’s report that Charlemagne later regretted having taken the imperial title is plausible.
This is a transcript from the video series Charlemagne: Father of Europe. Watch it now, on Wondrium.
Frankish Wars

Charlemagne’s fourteen years as emperor were, in some ways, rather different than his previous fifty-odd years. Yet, the differences between Emperor Charlemagne and his previous self often had more to do with the natural life cycle than with the imperial title.
The Franks continued to fight far-flung wars. Some of these wars were successful. In the late 790s, the Franks began launching destructive raids into northeastern Spain; in 801, they captured Barcelona, extending Frankish rule into what would one day be Catalonia. The Saxon Wars ended in 804 with Frankish victory as well. But elsewhere, and especially during the final decade of Charlemagne’s life, the Franks found themselves fighting to a draw more often than not.
Clashes with the Danish Vikings
Clashes with the Danish Vikings flared up in 808, and a large raiding party of Danish Vikings plundered the region of Frisia in 810. The Danish raid was perhaps a foretaste of the Viking attacks that would afflict the Frankish kingdoms on a much larger scale starting in the 830s, and that had been afflicting the British Isles since 793. The Franks pursued the Viking plunderers but could not catch them or give them battle.
Given Charlemagne’s inability to confront the Danish Vikings on his terms, it may have been a lucky break for the Franks when, in 810, the Danish king was murdered by a member of his court. Following the murder, the Danish Vikings focused on domestic conflicts rather than external ventures; they broke off their hostilities with Charlemagne, and never resumed them during the emperor’s lifetime.
Less Adventurous Than Before
Emperor Charlemagne, now in his fifties and sixties, campaigned less often in person and traveled less far afield than he had as a younger man. Even when he did campaign, he did not venture very far from the palace complex at Aachen.
He participated in the nearby wars against the Saxons and the Danes, but he no longer made the long journeys required to fight in more distant Italy or Spain. He never set foot in Rome again after 801. Instead, Charlemagne devoted more time to his favorite pursuits, hunting and swimming.
Common Questions about Charlemagne’s Coronation and his Later Years as Emperor
According to Charlemagne’s biographer Einhard, Charlemagne’s imperial coronation came as a surprise to Charlemagne himself. However, it seems almost certain that Charlemagne knew about the coronation beforehand and denied having this knowledge because of the modest image he wanted to keep and to avoid increasing tensions with the Byzantine Empire.
Charlemagne’s imperial coronation may have been seen as a direct threat to the Byzantine Empire. Since the Byzantine emperor held the title of ‘Emperor of the Romans’, Charlemagne’s title had to pose less of a threat.
Given Charlemagne’s inability to confront the Danish Vikings on his terms, it was a lucky break for the Franks when, in 810, the Danish king was murdered by a member of his court. Following the murder, the Danish Vikings focused on domestic conflicts rather than external ventures; they broke off their hostilities with Charlemagne, and never resumed them during the emperor’s lifetime.