A friend must be loyal. One believes his friends to be someone who will never betray him and help him out in different conditions.Here we see, Mark Antony joined conspirators in love for Rome and democracy. However, he must have given a thought on finding information from Julius, or to discuss the topic with him. He did nothing so and joined conspirators to assassinate Julius.At the end, Julius died saying "Yet tu, Brute!" as he expected him to be most loyal of senators and Brutus stabs him.