Julius Caesar by William Shakespeare was based on actual events which took place in 44 B.C. Shakespeare called this a political tragedy. Actually, no one wins in the final analysis. Only Octavius survives after the play and when the actual events continue. Each person made many mistakes.
Julius Caesar wanted to be the leader of the Roman Empire. He had come home victorious in many battles. Now, he will be offered the crown. One mistake he made that was unpopular was to be a part of the murder of Pompey who had been a popular leader and a friend of Caesar at one time. Caesar’s mistake is that he does not heed the warnings of danger that are given to him. His wife Calpurnia dreams and tells him that something bad will happen. The soothsayer gave him three warnings. Even the prophets using bones of animals told Caesar not to go to the Senate that day. Arrogantly, he listens to no one and is assassinated.
Marcus Brutus might be described as an intelligent, sensitive man who loved Rome more than anything. He made many decisions that were wrong throughout the play. He struggled with his decision to join the conspiracy but in the end this judgment impacted the rest of the play. He joined the assassins because he was afraid of the possibilities of what Caesar might do or might become. This was the beginning of the downfall of all the rest of the conspirators. He then was able to influence Cassius to make poor resolutions as well.
Caius Cassius was a strong soldier and Roman. He was a powerful senator. On the other hand, he had several faults: jealousy of Caesar, arrogance, self-pity. His mistake was to give in to Brutus and allow him to make many poor decisions. Cassius was more experienced in battle, in life, and he could see into the hearts of men and judge whether they were for Caesar or against him. Cassius wanted to kill Antony. Brutus over powered him on this. Cassius allowing Brutus to overrule him caused the death of all of the conspirators because Antony was able to infuriate the people of Rome against the conspirators.
Antony in Act IV, Scene I, shows an entirely different side than his patriotic, love of Caesar portrayal. Here is making a conscription list of who should live and who should die. The people who seemed to be against the new government of Lepidus, Antony, and Octavius would die. This portrayed Antony as someone who was willing to kill Roman citizen to better his personal cause. It was not a popular decision. Among them was the nephew of Antony. He traded his sister’s son for Lepidus’ brother:
Octavius: Your brother must die, consent you Lepidus?
Lepidus: I do consent--
Upon condition that Publius shall not live who is your sister's son Marc Antony.
Marc Antony: He shall not live. Look with a spot I damn him.
Based on their judgments, all of these men will be dead by the end of the play except for Antony. He soon will die by the hands of Octavius’s soldiers.
In Shakespeare's play (though perhaps not in actual history) Julius Caesar's most serious mistake is pretty obvlously not listening to the people who were warning him that his life was in danger. The main person warning him was his wife Calpurnia. The other was the Soothsayer who told him to beware the Ides of March. Then at the beginning of Act 2, Scene 3, Artemidorus has prepared a letter naming all the people who are plotting to assassinate Caesar, but the ambitious and egotistical Caesar refuses to read it when he arrives at the Capitol.
Brutus' most serious mistake is in letting Antony speak at Caesar's funeral, in spite of Cassius' urgent warnings against trusting the man who was Caesar's best friend. This famous speech is the turning point in the play.
I heard him say Brutus and Cassius
Are rid like madmen through the gates of Rome.
Cassius' most serious mistake is in persuading Brutus to be the leader of all the assassins. Once Brutus has agreed to take the lead, he becomes as pigheaded as Caesar and there is no controlling or guiding him. Perhaps Cassius should have tried to make Brutus feel he was more of an adviser and observer and benevolent supporter, if at all possible.
Mark Antony makes a lot of mistakes in Shakespeare's Antony and Cleopatra, but it is hard to think of any serious mistakes he makes in Julius Caesar. In fact, he plays it pretty cool considering the tight spot he is in after Caesar's death. Maybe his mistake was letting himself get drawn off by Trebonius.
Trebonius knows his time, for look you, Brutus,
He draws Mark Antony out of the way.
If Antony had been with Caesar he might have tried to defend him, but he could easily have gotten killed himself, and then the conspirators would have retained their power in Rome. Octavius would have had to stay away and perhaps even go into hiding.