To challenge, lay his lance in rest, charge, and unhorse his opponent, was an easy matter for Charlemagne.

When he learned that he had disarmed Elbegast (Alberich), the notorious highwayman, he promised to let him go free if he would only help him steal something that night.
Guided by Elbegast, Charlemagne, still incognito, went to the castle of one of his ministers, and, thanks to Elbegast's cunning, penetrated unseen into his bedroom.

There, crouching in the dark, Charlemagne overheard him confide to his wife a plot to murder the emperor on the morrow.

Patiently biding his time until they were sound asleep, Charlemagne picked up a worthless trifle, and noiselessly made his way out, returning home unseen.
On the morrow, profiting by the knowledge thus obtained, he cleverly outwitted the conspirators, whom he restored to favor only after they had solemnly sworn future loyalty.

As for Elbegast, he so admired the only man who had ever succeeded in conquering him that he renounced his dishonest profession to enter the emperor's service.
In gratitude for the heavenly vision vouchsafed him, the emperor named his new palace Ingelheim (Home of the Angel), a name which the place has borne ever since.