Final answer:
In Shakespeare's play 'Julius Caesar', Marc Antony is the first person to address the crowd after Caesar's assassination with a stirring speech.
Step-by-step explanation:
The first person to address the crowd after Caesar's assassination, as depicted in William Shakespeare's play Julius Caesar, was Marc Antony. Known for his loyalty to Caesar, Antony delivered a powerful oration that cleverly swayed the Roman populace against the conspirators, ultimately leading to a civil uproar. His speech contains the famous line, "Friends, Romans, countrymen, lend me your ears; I come to bury Caesar, not to praise him." Antony's speech is a pivotal moment in the narrative that influences the course of events following Caesar's death.