Question

Which quotation from Julius Caesar is an example of a historical allusion?

“MARULLUS. But what trade art thou? Answer me directly. / COBBLER. A trade, sir, that I hope I may use with a safe / conscience, which is indeed, sir, a mender of bad soles.” (act 1, scene 1)
“These growing feathers plucked from Caesar’s wing / Will make him fly an ordinary pitch,” (act 1, scene 1)
“CASSIUS. And why should Caesar be a tyrant then? / Poor man, I know he would not be a wolf / But that he sees the Romans are but sheep.” (act 1, scene 3)
“O, you hard hearts, you cruel men of Rome, / Knew you not Pompey?” (act 1, scene 1)

Answer 1

“O, you hard hearts, you cruel men of Rome, / Knew you not Pompey?” (act 1, scene 1)

This directly names Pompey — a real historical Roman leader and rival of Caesar — so it is a historical allusion.