One thing that Shakespeare focuses on in this play is how politicians must behave in order to stay in power (and stay alive). For Antony, in Act III, scene i, just after Caesar has been stabbed to death on the steps of the Capitol, staying alive is a crucial task. He was the man closest to Caesar, and was also, in fact, someone the Conspirators discussed killing also, since he was Caesar's "right arm." So, what Antony does in this scene, is absolutely vital to his staying alive.
The first description of Antony's reaction to the murder is a report from Trebonius that he has "fled to his house amazed." And then, just over 50 lines later, Antony enters the scene of Caesar's death. He speaks bravely of offering himself up to the Conspirator's knives, if they intend to kill him also. At this moment, Antony's displays his incredible bravery, as he stands in a room full of men who have just committed murder and says:
. . .there is no hour so fit
As Caesar's death's hour, nor no instruments
Of half that worth as those your swords, made rich
With the most noble blood of all this world.
I do beseech ye . . .
Fulfil your pleasure.
But they do not kill him. His next move is to shake the bloody hands of each of the Conspirators. He calls himself the murderers' friend and asks that they:
. . .give me reasons
Why and wherein Caesar was dangerous.
. . .That's all I seek.
And am, moreover, suitor that I may
Produce his body to the market place;
And in the pulpit, as becomes a friend,
Speak in the order of his funeral.
So Antony, asks that they answer why Caesar was dangerous and also requests to speak at his funeral. Antony is granted permission to speak at the funeral, and when the room is empty but for Antony, he is able to honestly show the audience how the murder has really affected him. He begins:
O pardon me, thou bleeding piece of earth,
That I am meek and gentle with these butchers!
And he goes on to prophesy that civil war will overtake Rome as a result of the Conspirators actions.
And Caesar's spirit, ranging for revenge,
. . .Shall in these confines with a monarch's voice
Cry 'Havoc,' and let slip the dogs of war. . .
And Antony, in his funeral oration, does indeed raise the mob to chaotic revolt and, ultimately, it is Antony who will rule as one of Rome's leaders, not Cassius or Brutus.
Directly after the assassination of Caesar, Antony is scared that the conspirators wish to kill him and sends his servant to them, to make sure that he will be safe. After Brutus assures Antony of his safety, Antony shakes hands with the conspirators, pretending to be on the same side as them. He does this to ensure his safety and so that Brutus will let him make a funeral oration. By feigning his alliance with the conspirators, Brutus is convinced that Antony is harmless and agrees to let Antony make a speech in honour of Caesar. We later find out this is a mistake, during Antony's soliloquy which states that he is going to take revenge upon the conspirators and "let loose the dogs of war." This shows Antony's loyalty towards Caesar and the closeness of their relationship.