Caesar enters with Antony, Calpurnia, Portia, Decius, Cicero, Brutus, Cassius, and Casca, followed by a Soothsayer and many Plebeians, and Murellus and Flavius. Caesar instructs his friend Antony, who is naked in accordance with his duty of "running the course" in a holiday ceremony, to touch Calpurnia as he runs, because tradition holds that infertile women may be cured this way.
Antony's nakedness symbolizes his emotional nature. Caesar's request of him establishes that Caesar is superstitious, and also hints at his ambition to become king, since he's concerned with having an heir.
The Soothsayer warns Caesar to "Beware the ides of March" (1.2.19), but Caesar ignores his warning.
Although Caesar is superstitious, he thinks himself invulnerable.
The procession passes, except for Brutus and Cassius, two high-ranking Romans. Brutus has no interest in watching the festivities, and says Cassius should go on without him.
Establishes Brutus as thoughtful and deferent, but also stoic and humorless, immediately contrasting him with the vibrant Antony.
Cassius remarks that Brutus has acted strangely lately, and wonders whether they are still friends. Brutus says that he's been worried by personal problems, and apologizes for being unsociable.
Brutus is introverted and oblivious to other peoples' impressions. Cassius has a knack for manipulating people and controlling conversation.
Cassius says that Brutus is greatly admired by all of Rome, and that everyone—"except immortal Caesar" (1.2.62)—wishes Brutus knew this. Brutus wonders why Cassius is trying to make him proud, since he knows vanity would be uncharacteristic of him. Cassius says he'll make Brutus realize just how admired he is, and that Brutus can trust him because he's respected and honest.
Cassius is not appealing to Brutus's vanity—Brutus has none—but to Brutus' great sense of responsibility towards Rome. Cassius is trying to insinuate that Caesar means to become all-powerful by sarcastically calling him "immortal.".
They hear cheering, and Brutus says he fears that Caesar is being crowned king. Cassius says that this possibility must displease Brutus, if he fears it.
Cassius puts words in Brutus's mouth, but makes them seem like Brutus' own ideas.
Brutus admits he is against the idea, although he loves Caesar, and asks Cassius to get to the point, saying that if it involves honor and the good of Rome, he'll face death to achieve it.
Establishes Brutus's conflict (his affection for Caesar versus his political ideals), and character (he always puts Rome ahead of himself).
Cassius says that he would rather be dead than bow to Caesar, since Caesar is no better than they. He tells Brutus about the time he saved Caesar's life while swimming, and about how Caesar once fell ill on a campaign in Spain. Cassius adds that he thinks that it is ironic that Caesar should seem so all-powerful now.
Cassius claims to speak for himself, but intends to persuade. He also changes tactics, having previously called Caesar "immortal," then saying Caesar is equal to them, and finally painting him as inferior, even feminine.
They hear more cheering. Cassius says that they cannot blame fate for their subservient positions: "The fault, dear Brutus, is not in our stars, / But in ourselves, that we are underlings" (1.2.141-2). He then asks why Caesar should be more honored than Brutus, and brings up Brutus's famous ancestor who drove the Tarquin kings out of Rome and helped establish the Republic.
After belittling Caesar, Cassius returns to describing his greatness, which now seems ironic. He then touches three themes he knows will affect Brutus: Roman tradition, the image of Rome to other nations, and the honor of Brutus's family.
Brutus says he understands what Cassius is getting at, and that it's been troubling him too, but that he'd rather talk about it later, adding that he'd rather not be Roman at all than be ruled by a king.
We never find out what Brutus was thinking before this, or what he might have done on his own, without Cassius's influence.
Cassius is glad his "weak words" (1.2.177) were effective, and suggests they ask Casca what they missed, as Caesar's procession returns. Brutus says Caesar looks angry, and the others look like they've been scolded.
Cassius claims he's ineloquent when he's obviously persuasive. The attention paid to Caesar's expressions confirms the imposing greatness Cassius has been denying.
As he passes in the procession, Caesar tells Antony that Cassius looks too "lean and hungry" (1.2.195) to be trusted, saying it's safer to be surrounded by fat, lazy men. Antony says Cassius can be trusted. Caesar says Cassius is too intellectual and cannot enjoy himself, and that such men are to be feared, but quickly points out that he only speaks rhetorically, not personally, because he himself fears nothing. Caesar asks Antony for more of his opinion of Cassius, telling him to speak into his good right ear. The procession exits, leaving Cassius, Brutus, and Casca.
Caesar is of course correct to suspect Cassius; this demonstrates the political acumen that has helped make him so powerful, while showing that Antony still has much to learn. This scene could be used to make a case for Caesar's alleged ambition: he must be planning something, if he fears perceptive men. Caesar's partial deafness contrasts with his immense political power.
Once Caesar is gone, Casca tells Brutus and Cassius that Antony offered Caesar a crown three times, and that Caesar refused it, causing the crowd to cheer, but seemed to find it harder to refuse each time, and finally had an epileptic seizure. Casca adds that before the fit, Caesar courted the favor of the crowd by offering them his throat to cut, implying that he would die for the people. Casca adds that privately he wished he could have cut Caesar's throat himself.
Casca is a cynic. This is reflected by his belief that Caesar's gestures before the crowd were phony, and by the fact that he speaks in colloquial prose while the others speak blank verse. Caesar's epilepsy, like his deafness, is another ironic contrast to his power.
Casca goes on to say that the famous orator Cicero addressed the crowd in Greek, which he did not understand, and that Murellus and Flavius have been removed from their offices as tribunes because they took the wreaths from Caesar's statues.
Both of these events reflect the fact that secrecy and division are spreading among the powerful, as well as the importance of controlling the populace.
Cassius makes arrangements to meet with both Casca and Brutus the next day, and the others exit. Alone, Cassius says that though Brutus is too honorable now to be influenced, he plans to throw messages through Brutus's windows that night, praising Brutus's honor and impugning Caesar's ambition, and that afterwards it will be easier to move Brutus against Caesar.
The fact that Cassius must resort to trickery to persuade Brutus is evidence that he does not believe his cause to be just. His chosen method is evidence of Brutus's great sense of duty towards Rome and its people.