Plutarch makes much of Antonius' "hardness in adversity notwithstanding his fine bringing up." Shakespeare knew these words very well; in fact, his copy of Plutarch was open to this exact sentence when he mended his quill and began to compose the famous speech in Anthony and Cleopatra that begins "Anthony, leave thy lascivious wassails."
Here are Plutarch's words (exactly as they came to Shakespeare through Sir Thomas North's translation). The passage that particularly stimulated the playwright appears (thanks to the magic of word processing), in a font of vivid blue.
"Hirtius and Pansa, then consuls [were sent by Octavius Caesar] to drive Antonius out of Italy. These two consuls... besieged the city of Modena, and there overthrew him in battle, but both the consuls were slain there. Antonius, flying upon this overthrow, fell into great misery all at once, but the chiefest want of all other, and that pinched him most, was famine. Howbeit, he was of such a strong nature that by patience he would overcome any adversity, and the heavier fortune lay upon him, the more constant showed he himself.... And therefore it was a wonderful example to the soldiers, to see Antonius, that was brought up in all fineness and superfluity, so easily to drink puddle water, and eat wild fruits and roots; and moreover it is reported that even as they passed the Alps, they did eat the bark of trees, and such beasts as man never tasted of their flesh before.
Shakespeare kept the sense of the passage but put Plutarch's words into the mouth of Octavius Caesar, who despises, envies, but also fears Anthony, his absent rival.
Anthony,
Leave thy lascivious wassails. When thou once
Was beaten from Modena, where thou slew'st
Hirtius and Pansa, consuls, at thy heel
Did famine follow, who thou fought'st against,
(Though daintily brought up) with patience more
Than savages could suffer. Thou did'st drink
The stale of horses, and the gilded puddle
Which beasts would cough at. Thy palate then did deign
The roughest berry on the rudest hedge.
Yea, like the stag, when snow the pasture sheets,
The barks of trees thou browsed. On the Alps,
It is reported thou did'st eat strange flesh,
Which some did die to look on. And all this
(It wounds thine honor that I speak it now)
Was born so like a soldier, that thy cheek
So much as lanked not.
Plutarch is shocked that high-born Antonius could bring himself to eat "wild fruits," but Shakespeare, ever willing to push an idea to the limit, makes Anthony's diet even more crude. "Thy palate then did deign [i.e. find worthy]/ The roughest berry on the rudest hedge" -- that is to say, Anthony eats not just "wild fruit," but the less palatable "roughest berry." In an even harsher transformation, Plutarch's "puddle water" becomes "the stale (i.e. urine) of horses, and the gilded puddle/ Which beasts would cough at." It may be stoic to drink "puddle water," but it is a far greater challenge to a dainty constitution to survive on horse piss. As the passage continues, Anthony's diet becomes progressively more exotic. Plutarch says that Antonius consumed "beasts as man never tasted of their flesh before," and seems to imagine Antonius as an adventurer at the utmost boundary of culinary experience. But when Shakespeare suggests that Anthony ate "strange flesh/ Which some did die to look upon," Anthony becomes not just a soldier/explorer coping with natural adversity but a demi-god or some other kind of supernatural figure able to triumph over enchantment or magic -- one who can incorporate fleshly food that would kill at a glance men with natures less powerful than his own.
Shakespeare characteristically intensifies, exaggerates, or hyperbolizes Plutarch's already extravagant tale. He raises the rhetorical ante. Whatever Plutarch proffers, Shakespeare doubles and redoubles.
The animal theme that runs through this series of transformations begins with the evolution of Plutarch's phrase "by patience he would overcome any adversity" into Shakespeare's "patience more than savages could suffer." More patience than savages? What would that be? Shakespeare provides an answer to an implicit, unspoken question, which is, What is a more, or worse, or a lower being than a savage? The answer seems to be "an animal" -- and consequently Shakespeare employs images of bestiality throughout this speech: the horses whose stale must be guzzled, the beasts who cough at the gilded puddle, the stag who browses the bark of trees under sheets of snow, and, climatically, the strange magical flesh that some -- but not Anthony -- die to look upon. In a characteristically Shakespearean paradox, as the passage proceeds Anthony becomes both more animal and more heroic -- at the same time both baser and yet more transcendent.
And what is that strange and magic Alpine flesh? It's impossible to say, and Shakespeare offers no clue. Perhaps it's mere hyperbole -- an author carried away by his own rhetorical power. Does Anthony violate the ultimate food taboo and become a cannibal? Some readers have thought so, but the evidence is lacking.
There is, however, a hint that Octavius himself thinks that the strange flesh episode is nothing more than a tall tale. "On the Alps, it is reported.... "