Battle of Roncevaux Pass
Basques wipe out Charlemagne's rearguard: the Song of Roland

On 15 August 778, as Charlemagne's army returned from a campaign in Spain, Basques ambushed and destroyed its rearguard in the Pyrenees. Among the dead was Hruodland, prefect of the Breton March, the future Roland of the epic.
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Meanwhile around the world (±25 years)
Middle East
- 762 Founding of Baghdad — 16 years earlier
Asia
- 755 The An Lushan Rebellion — 23 years earlier
- c. 760 Kailasa Temple at Ellora — 18 years earlier
- 802 Founding of the Khmer Empire — 24 years later
Americas
- c. 800–950 Drought and the Classic Maya collapse — 22 years later
Alive at the time
- Charlemagne (aged 30)
- Emperor Kanmu (aged 41)
- Harun al-Rashid (aged 12)
- Louis the Pious (aged 0)