Antony despises Lepidus and speaks of him with contempt in Act 4, Scene 1 of Julius Caesar, after he has sent Lepidus off on an errand and is alone with young Octavius.
This is a slight unmeritable man,
Meet to be sent on errands: is it fit,
The three-fold world divided, he should stand
One of the three to share it?
So you thought him;
And took his voice who should be prick'd to die,
In our black sentence and proscription.
Octavius, I have seen more days than you:
And though we lay these honours on this man,
To ease ourselves of divers slanderous loads,
He shall but bear them as the ass bears gold,
To groan and sweat under the business,
Either led or driven, as we point the way;
And having brought our treasure where we will,
Then take we down his load, and turn him off,
Like to the empty ass, to shake his ears,
And graze in commons.
A bit later he adds the following scathing remark about Lepidus:
A barren-spirited fellow; one that feeds
On abjects, orts and imitations,
Which, out of use and staled by other men,
Begin his fashion: do not talk of him,
But as a property.
Lepidus remains a member of the triumvirate for some time, but the Roman empire is effectively divided between Antony and Octavius. Antony assumes military and political control of the eastern part of the empire with his headquarters in Egypt, where he gets involved with the exotic and cunning Queen Cleopatra.
This part of Roman history became the subject of Shakespeare's Antony and Cleopatra, in which Lepidus has a small part and is depicted as a foolish man who is held in contempt even by the servants of Pompey, who is hosting a party for the three men aboard his ship. Lepidus last appears in Act 2, Scene 7 of Antony and Cleopatra, where he is eventually carried offstage in a drunken stupor. In this scene Antony treats Lepidus with great contempt and ridicule. Lepidus is shown flattering both Antony and Octavius, evidently trying rather desperately to maintain his position as the third member of the triumvirate. It is obvious that there is no place for him and that his days are numbered.
In Act 2, Scene 7 of Antony and Cleopatra, Octavius is depicted as a cold, calculating, extremely intelligent and rational man who remains cold sober while the other men, including the self-indulgent Mark Antony, are getting drunk. It seems obvious in this critical scene that Octavius will eventually become the sole ruler of the Roman Empire.