Act Four, Scene One
Antony, Octavius and Lepidus have banded together in a counter-conspiracy to destroy the men who killed Caesar. Antony has a paper with names on it and he says, "These many, then, shall die; their names are pricked" (4.1.1). The men then mark more names of people who must die, including the brother of Lepidus and the son of Mark Antony's sister. Antony states that, "He shall not live. Look, with a spot I damn him" (4.1.6).
Antony then sends Lepidus to Caesar's house to fetch the will. He hopes to somehow reduce the amount of money that needs to be paid to the beneficiaries. After Lepidus leaves, Antony tells Octavius that Lepidus was a poor choice to form the second triumvirate with. Octavius says, "You may do your will; / But he's a tried and valiant soldier" (4.1.28). Antony implies in his speech that he will eventually remove Lepidus from rule, but that they should keep him a while longer.
Act Four, Scene Two
Brutus has brought his armies to Sardis (now Western Turkey) and has set up camp. A messenger whom he sent to Cassius informs him that Cassius is not as friendly anymore. Brutus remarks, "Thou hast described / A hot friend cooling" (4.2.18-19). At that moment Cassius' army arrives and Cassius himself appears. He is angry with Brutus and starts to accuse him of wronging him, but Brutus makes him enter the tent so that they do not appear to be fighting in front of their men.
Cassius is upset that Brutus publicly disgraced a friend of his for taking bribes from the Sardians. Apparently Cassius had sent several letter to Brutus urging for the man's release, but Brutus refused. Brutus is furious that Cassius would even consider defending a man for taking bribes, arguing that Caesar was killed for exactly such behavior. He states, "What, shall one of us, / That struck the foremost man of all this world / But for supporting robbers, shall we now / Contaminate our fingers with base bribes" (4.2.73-76). Cassius and Brutus end up threatening each other, with each man convinced he is better able to lead the armies than the other.
The two men continue arguing, and Brutus finally tells Cassius that he is upset that Cassius refused to send him gold with which to pay his soldiers. Brutus says, "I did send / To you for gold to pay my legions, / Which you denied me" (4.2.130-132). Cassius denies it, and in exasperation pulls out his dagger and offers it to Brutus. He tells Brutus to kill him if he is such an terrible man, but Brutus recants and they finally embrace in friendship.
A poet forces his way into the tent and demands that the generals (Cassius and Brutus) not be left alone. He argues that there is a grudge between them. However, having already resumed their friendship, they order him away.
Brutus finally informs Cassius that Portia is dead. Cassius, is surprised by the news and asks how she died. Brutus explains that Portia, left alone in the city after he fled, was upset that Octavius and Antony had seized control of Rome. She therefore took live embers and swallowed them, killing herself. Titinius and Messala arrive and Brutus immediately changes the subject. Cassius takes him aside and asks, "Portia, art thou gone?" (4.2.218). Brutus tells him not to speak of her anymore.
Brutus and Messala compare letters they have received informing them that Antony and Octavius are marching towards them from Greece. Messala tells Brutus that over one hundred senators have been put to death, but Brutus says his letter only mentioned seventy, including the orator Cicero. Messala then asks Brutus if he has heard anything about Portia, to which Brutus replies, "Nothing, Messala" (4.2.236), and asks Messala for news of her, pretending to hear of her death for the first time.
Brutus and Cassius then decide whether to wait for Antony and Octavius in Sardis or march to meet the opposing army in Philippi. Cassius prefers to wait and keep his men fresh, but Brutus thinks that the enemy is gaining in power every day and therefore must be stopped as soon as possible. Cassius finally agrees with him and leaves for his tent to rest before leaving in the morning.
Brutus remains awake with his servant Lucius. He orders two men, Claudio and Varrus, to enter his tent and sleep there in case he needs to send them on an errand during the night. Brutus then asks Lucius to play him a song on his stringed instrument, which he does until he falls asleep with his instrument in his hands.
Brutus starts reading a book, but the ghost of Julius Caesar appears, causing the flame to dim. Brutus demands to know who has entered the room, and the ghost tells him, "Thy evil spirit, Brutus" (4.2.333). Brutus then asks the ghost why he has come, and is told that the ghost will see him again at Philippi. The ghost leaves, and Brutus immediately wakes up everyone else in the room. He orders Lucius to go back to sleep, and tells Varrus and Claudio to inform Cassius that he should take his army and march ahead.
Antony, Octavius and Lepidus differ significantly from the original conspirators. They wish only to avenge Caesar's death and are willing to murder each of them, stating "These many, then, shall die; their names are pricked" (4.1.1). In their counter-conspiracy, they are willing to include relatives and friends on the list of those to die, demonstrating they are most serious and dedicated to the task of eradicating those who conspired against Caesar. Antony's statement, "He shall not live. Look, with a spot I damn him" (4.1.6) brings to the forefront the calculating nature of the new rulers.
Brutus stands out as an example of Republican stoicism on the battlefield. He describes the cause of Portia's death as, "Impatience of my absence" (4.2.204). His calmness when speaking about his wife's death frightens even Cassius, who remarks that, "How scaped I killing when I crossed you so?" (4.2.202). He is further taken aback by the ease with which Brutus dismisses the topic when Titinius and Messala arrive. Brutus immediately changes the subject, forcing Cassius to take him aside and ask, "Portia, art thou gone?" (4.2.218). Brutus tells him not to speak of her anymore. Later, when Messala asks Brutus if he has heard anything about Portia, Brutus replies, "Nothing, Messala" (4.2.236). Stoicism and honor mean everything to Brutus, and like Hotspur in Henry IV, Brutus refuses to show weakness to his troops.
Letters and poetry appear a great deal throughout this play, possibly more than in any other of Shakespeare's plays. In the first act, Cassius writes anonymous letters to Brutus to convince him to joint he conspiracy, Artemidorus writes an ignored letter warning Caesar of the plot against him, and Cinna the poet is murdered. In this act, a poet again takes the stage, but Brutus orders him removed from his tent. In addition, both Brutus and Messala have letters regarding the state of Rome after Antony's speech. Brutus states, "Mine [a letter] speaks of seventy senators that died / By their proscriptions, Cicero being one" (4.2.229-230). This mention of perhaps the greatest orator Cicero, a man identified closely with words, is almost an afterthought. Even Brutus, when trying to read his book, is unable to continue reading because the ghost of Caesar interrupts him. We therefore see first the manipulative power, and then the destruction and dismissal of literature and poetry after Caesar's death.