Some time in the early ninth century AD, a Frankish scholar named Einhard sat down to write a biography. His theme was a worthy one. Charlemagne, the greatest king of his age, had died in 814, after a reign of almost 50 years. During that time he had won many wars, sponsored numerous reforms and served as the patron of a golden age of learning. The surest measure of his achievements was that in 800, in Rome itself, he had been crowned emperor: the heir of the Caesars.

Centuries might have passed since the collapse of Roman rule in western Europe, but the allure, the charisma, the prestige of the vanished empire still haunted Frankish scholars. This was why, when Einhard sought a model for his biography of Charlemagne, he turned not to a recent source, not to the life of a saint or a Christian ruler, but to an older text by far.

New Statesman