O! You and I have heard our fathers say
There was a Brutus once that would have brooked
Th’eternal Divel to keep his state in Rome
As easily as a King (I.ii)

Here, Cassius is speaking to Brutus about the founder of the Roman Republic, Lucius Junius Brutus, who banished the oppressive Tarquin kings from the city in 509 BCE From that point on, Rome was governed by Consuls, typically two at a time, who were democratically elected by the Senate every year. In this scene, Cassius appeals to Brutus’ pedigree, invoking his famous ancestor who, Cassius suggests, would have tolerated governance by the Devil himself before he would have tolerated a king. Trying to recruit Brutus to his side, Cassius appeals to his friend’s righteous allergy to monarchy and one-man rule. Given the historical precedent of the Tarquin tyrants, the threat of another dictatorship looms large in the play, and serves as the main catalyst for Caesar’s murder.

No, Caesar hath it not, but you and I
And honest Casca, we have the falling sickness (I.ii)

In this part of the scene, Casca has told Brutus and Cassius that Caesar fainted before the crowd at the Lupercalia festivities in a minor fit. It was a poorly kept secret that Julius Caesar had “the falling sickness” or epilepsy. Speaking these lines, Cassius, suggests that it is the three of them, not Caesar, that have the “falling sickness,” because they are complacent in allowing Caesar to seize monarchical power. Again, Cassius here is working to nudge Brutus into a conspiracy to topple Caesar. Raising the specter of tyranny seems to be his main strategy in eliciting his colleague’s participation. More importantly, Cassius suggests that tyranny is not merely the fault of one ambitious, power-grabbing individual, but also of those who stand by and allow it to happen.

And why should Caesar be a tyrant then?
Poor man, I know he would not be a wolf,
But that he sees the Romans are but sheep (I.iii)

During the ominous storm at the end of Act I, Cassius tells Casca that Caesar is not tyrannical in nature, but that he could easily become corrupted by the enormous influence he now wields. Caesar will soon discover how easily the people of Rome can be manipulated, and he will not be able to resist the temptation to abuse his power. This introduces a vital layer of complexity to Julius Caesar. The question is not simply whether Caesar is an evil oppressor of the people—he is not (at least not yet)—but whether he will become one in the future. Power is naturally corrosive, Cassius insists, but is this a persuasive excuse for taking Caesar’s life? Ultimately, the public will decide.