This passage is of great significance in Shakespeare’s delineation of Octavius, because, though suggested by Plutarch, it completely alters the complexion and some of the facts of Plutarch’s story. That records the two-fold challenge of Antony, but represents it as answering, not preceding the message of Octavius. Moreover that message contains no reference to a naval combat and has nothing in common with the shape it assumes in the play.
Octavius Caesar sent unto Antonius, to will him to delay no more time, but to come on with his army into Italy: and that for his owne part he would give him safe harber, to lande without any trouble, and that he would withdraw his armie from the sea, as farre as one horse could runne, until he had put his army ashore, and had lodged his men.
That is, in the original Octavius takes the lead in dare-devilry, and seems voluntarily to suggest such terms as even Byrhtnoth at the Battle of Maldon conceded only by request. Shakespeare could not fit this in with his conception of the cold-blooded politician, and substitutes for it a proposal that will put the enemy at a disadvantage; while at the same time he accentuates Octavius’ unblushing knavery, by making him apply this provocation after he has twice rejected offers that do not suit himself.
Again, having won his first victory through Cleopatra’s flight, Caesar cynically reckons for new success on her corruptibility:
From Antony win Cleopatra: promise,
And in our name, what she requires; add more,
From thine invention, offers: women are not
In their best fortunes strong; but want will perjure
The ne’er-touch’d vestal: try thy cunning, Thyreus.
(III. xii. 24.)