Plutarch, Quomodo adulator ab amico internoscatur
Goodwin, Ed.

There remains yet another way to discover him by his inclinations towards your intimates and familiars. For there is nothing more agreeable to a true and cordial acquaintance than to love and to be beloved with many; and therefore he always sedulously endeavors to gain his friend the affections and esteem of other men. For being of opinion that all things ought to be in common amongst friends, he thinks nothing ought to be more so than they themselves. But the faithless, the adulterate friend of base alloy, who is conscious to himself of the disservice he does true friendship by that false coin of it which he puts upon us, is naturally full of emulation and envy, even towards those of his own profession, endeavoring to outdo them in their common talent of babbling and buffoonry, whilst he reveres and cringes to his betters, whom he dares no more vie with than a footman with a Lydian chariot, or lead (to use Simonides's expression) with refined gold. Therefore this light and empty counterfeit, finding he wants weight when put into the balance against a solid and substantial friend, endeavors to remove him as far as he can, like him who, having painted a cock extremely ill, commanded his servant to take the original out of sight; and if he cannot compass his design, then he proceeds to compliment and ceremony, pretending outwardly to admire him as a [p. 137] person far beyond himself, whilst by secret calumnies he blackens and undermines him. And if these chance to have galled and fretted him only and have not thoroughly done their work, then he betakes himself to the advice of Medius, that arch parasite and enemy to the Macedonian nobility, and chief of all that numerous train which Alexander entertained in his court. This man taught his disciples to slander boldly and push home their calumnies; for, though the wound might probably be cured and skinned over again, yet the teeth of slander would be sure to leave a scar behind them. By these scars, or (to speak more properly) gangrenes and cancers of false accusations, fell the brave Callisthenes, Parmenio, and Philotas; whilst Alexander himself became an easy prey to an Agnon, Bagoas, Agesias, and Demetrius, who tricked him up like a barbarian statue, and paid the mortal the adoration due to a God. So great a charm is flattery, and, as it seems, the greatest with those we think the greatest men; for the exalted thoughts they entertain of themselves, and the desire of a universal concurrence in the same opinion from others, both add courage to the flatterer and credit to his impostures. Hills and mountains indeed are not easily taken by stratagem or ambuscade; but a weak mind, swollen big and lofty by fortune, birth, or the like, lies naked to the assaults of every mean and petty aggressor.