And in what manner did this philosopher comfort him for the loss of such a man, and heal his conscience, flagrant with the smart of such a crime?
You have the matter at length in Plutarch.

He told him, "_that let a sovereign do what he wilt, all his actions are just and lawful, because they are his_." The palaces of all princes abound with such courtly philosophers.

The consequence was such as might be expected.

He grew every day a monster more abandoned to unnatural lust, to debauchery, to drunkenness, and to murder.

And yet this was originally a great man, of uncommon capacity, and a strong propensity to virtue.