Bellarion the Fortunate by Rafael Sabatini

"Half god, half beast," the Princess Valeria once described him, without suspecting that the phrase describes not merely Bellarion, but Man.

Aware of this, the anonymous chronicler who has preserved it for us goes on to comment that the Princess said at once too much and too little. He makes phrases in his turn -- which I will spare you -- and seeks to prove, that, if the moieties of divinity and beastliness are equally balanced in a man, that man will be neither good nor bad. Then he passes on to show us a certain poor swineherd, who rose to ultimate eminence, in whom the godly part so far predominated that naught else was humanly discernible, and a great prince -- of whom more will be heard in the course of this narrative -- who was just as the beasts that perish, without any spark of divinity to exalt him. These are the extremes. For each of the dozen or so intermediate stages which he discerns, our chronicler has a portrait out of history, of which his learning appears to be considerable.