772 · Saxony (northern Germany) Theater

Charlemagne opened his longest war by invading pagan Saxony, storming the fortress of Eresburg and destroying the Irminsul — a great sacred pillar or tree-trunk at the heart of Saxon religion. It was the first blow in a struggle to conquer and forcibly Christianise the fiercely independent Saxon tribes that would drag on for more than thirty years.

773 – 774 · Northern Italy Theater

Answering the Pope's appeal against the Lombards, Charlemagne crossed the Alps and besieged the Lombard capital of Pavia through the winter. When the city surrendered in 774, he deposed and imprisoned King Desiderius, took the Iron Crown of the Lombards for himself, and annexed the kingdom of Italy to his own realm.

August 15, 778 · The Pyrenees (Spanish frontier) Theater

Retreating from an inconclusive campaign in Muslim Spain, Charlemagne's army had to recross the Pyrenees. In the narrow pass of Roncevaux, Basque warriors ambushed and annihilated the Frankish rearguard, killing its commander Roland and other great nobles before vanishing into the mountains with the baggage.

782 · Saxony (northern Germany) Theater

After a Saxon uprising under Widukind destroyed a Frankish army in the Süntel hills, an enraged Charlemagne demanded the surrender of the rebels. At Verden he had some 4,500 captured Saxons beheaded in a single day — one of the most notorious atrocities of the early Middle Ages.

785 · Saxony (northern Germany) Theater

After years of relentless campaigning, deportations, and the imposition of a savage law-code that made Saxon paganism a capital crime, the great Saxon leader Widukind finally despaired of victory. In 785 he submitted and accepted Christian baptism, with Charlemagne himself standing as his godfather. Saxon resistance was broken — for a time.

788 · Bavaria Theater

Charlemagne moved against his cousin Duke Tassilo III, the last great independent ruler within the Frankish sphere, accusing him of treason and conspiracy with the Avars. Tassilo was deposed, forced into a monastery, and Bavaria was absorbed directly into the Frankish realm — largely without a battle.

791 – 796 · Pannonia (the Hungarian plain) Theater

Charlemagne turned against the Avars, the steppe people who had dominated the Danube basin for two centuries and terrorised their neighbours. In a series of campaigns his armies broke into the Avar heartland, and in 795–796 they captured the great fortified 'Ring' — the Avar treasury — seizing centuries of accumulated plunder, which took fifteen wagons drawn by oxen to carry away.

December 25, 800 · Rome Theater

On Christmas Day 800, in St Peter's Basilica in Rome, Pope Leo III placed a crown on Charlemagne's head and the assembled Romans acclaimed him 'Emperor of the Romans.' The Roman imperial title, extinct in the West for over three centuries, was revived in the person of the Frankish king.

801 · Catalonia (the Spanish frontier) Theater

Charlemagne's son Louis, King of Aquitaine, captured the city of Barcelona from the Muslims after a long siege, extending Frankish power south of the Pyrenees and establishing the fortified frontier zone known as the Spanish March.

804 · Saxony (northern Germany) Theater

To break the last Saxon resistance north of the Elbe, Charlemagne resorted to mass deportation, uprooting many thousands of Saxons from their homeland and resettling them across the empire while planting Frankish and Slav settlers in their place. By 804, after thirty-two years, Saxony was finally, brutally pacified and absorbed.