In Act l, Scene 2, Casca tells Brutus that Caesar refused the crown from Antony. Casca said " I saw Mark Antony offer him a crown...as I told you, he put it by once" (l : ii : line 235-237). This is important because it makes Brutus question if Caesar is harmful or innocent. Although their is uncertainty the conspirators know Caesar wants all the power and will do anything to get it.
Act IV : Sc 3
In Act 2, Scene 1, Brutus decides that it is time to take Caesar out for the better of the Roman people. Brutus says " And therefore think him as a serpent's egg..and kill him in the shell" ( ll : i : line 32-34). When Brutus makes his final decision an anonymous letter is received telling Brutus that he is better for the Roman people. That letter is the start of the conspirators plan for killing Caesar.
Act V : Sc 3
In Act lll, Scene 1, When Casca calls out " Speak hands for me!" ( lll : i : line 78), all the conspirators attack Caesar. The towns people are in shock with the killing of Caesar. After Caesar's death the conspirators have to win over the towns peoples trust by saying they were honorable men for doing this deed. With Brutus trusting Antony about saying they were honorable men, Antony persuaded the towns people against the conspirators.
In Act lV, Scene 3, The ghost of Caesar showed up in Brutus's room. Caesar's ghost says " To tell thee thou shalt see me at Philippi" (Act IV : iii : line 283). This urges Brutus to wake everyone up and march to Philippi. The ghost warns Brutus about seeing them at Philippi, but Brutus still marches on to fight.
In Act V, Scene 3, At the end of the battle all of the conspirators are dead. Mark Antony calls Brutus “ the noblest of them all ” ( V : iii : line 68). Antony sees how Brutus was an honest and true Roman for taking his own life. Everyone knew the ghost of Caesar was still alive and that’s how the battle was won.
The theme of Julius Caesar is ambition. Caesar ambition worries Brutus which causes Brutus to join the conspirators to kill Caesar. Cassius is also ambitious because he is jealous of Caesar. This makes Cassius want to kill Caesar and get all the power.