He spoke German, Spanish, Italian, French, and Flemish, and could assume the characteristics of each country as easily as he could use its language.

He could be stately with Spaniards, familiar with Flemings witty with Italians.

He could strike down a bull in the ring like a matador at Madrid, or win the prize in the tourney like a knight of old; he could ride at the ring with the Flemish nobles, hit the popinjay with his crossbow among Antwerp artisans, or drink beer and exchange rude jests with the boors of Brabant.

For virtues such as these, his grave crimes against God and man, against religion and chartered and solemnly-sworn rights have been palliated, as if oppression became more tolerable because the oppressor was an accomplished linguist and a good marksman.
But the great reason for his popularity no doubt lay in his military genius.

Charles was inferior to no general of his age.