500
Julius Caesar says, "Et tu, Brutus? Then fall Caesar."
What does this mean, and why does he says this?
"You too, Brutus? Then I will die."
If even his closest friend is willing to conspire against him, then he might as well die because there is no more hope.
OR
If even his closest friend feels that this is the right thing to do, then he will agree to fall as well.