Final answer:
Shakespeare used Plutarch's historical writings as a source for his play Julius Caesar, which provided details on Caesar's life and the events leading to his assassination.
Step-by-step explanation:
William Shakespeare used the works of Plutarch, an ancient Roman historian, as a source for writing his play Julius Caesar. Plutarch's Lives of the Noble Greeks and Romans, specifically the life of Julius Caesar, provided Shakespeare with historical details about Julius Caesar's dictatorship and the political drama leading to his assassination. Shakespeare's portrayal of historical events in the play was heavily influenced by Plutarch's narratives.