Charlemagne’s Holy Roman Empire
Charlemagne ended his reign as he began it: by fighting to defend his capital at Aix la Chapelle (now Aachen). First he fought the neighboring Saxons. In the end, he fought the Danes, who were part of the Scandinavian expansion that grew with the onset of a five-century warming trend (800 to 1300). By then he was an old man of 70. The Danes exhausted him. He was carried back on a litter and . . .