When Brutus and Cassius meet in Brutus’s tent in Act IV, sc iii of the play, they have a massive falling out. It is the only time that they are really seen to be at odds with each other, but this scene between them is unexpectedly bitter. They accuse each other of various misdemeanours, Brutus complaining of Cassius taking bribes and withholding money from him while Cassius charges Brutus with ill-treatment of a friend.
However, these issues are relatively superficial; there are deeper underlying reasons for the tension. Things have not been looking good for the pair ever since Antony’s rousing speech at Caesar’s funeral turned the people of Rome against them; and Antony has now joined forces with Octavius Caesar, Julius’s nephew.
In short, what they hoped for following the killing of Caesar has not materialised; quite the opposite. Far from being won to their cause, the ordinary people of Rome are now baying for their blood, and Antony and Octavius Caesar have powerful forces to array against them. Instead of the republic being safeguarded, Rome is on the brink of a brutal civil war. Their actions have helped destabilise the entire state.
It is no wonder therefore if both of them are on edge, Brutus particularly as he has seen the collapse of his political dream for Rome, although he still appears to cling to the idealism that spurred him to the assassination of Caesar:
Did not great Julius bleed for justice’s sake?
What villain touched his body, that did stab
And not for justice? (IV.iii.19-21)
Brutus blames Cassius for undermining the idealistic notions behind the assassination by taking bribes (24). We may wonder, though, if there is not a deeper reason for him lashing out in this manner; maybe he now regrets joining Cassius’s side against Caesar in the first place, as it has all turned out so badly. With that said, his temper does die down quickly enough when he realises just how hurt Cassius is by the quarrel. Their friendship survives this test.
Another reason emerges for Brutus’s quick temper in this scene; it transpires that he has received news of his wife Portia’s suicide. Cassius is remorseful on hearing this, and the two are fully reconciled; but there is greater calamity yet to come for both of them.