Of Shakespeare's ten tragic plays, four are set in ancient Rome: Titus Andronicus, Antony and Cleopatra, Julius Caesar, and Coriolanus. All, but in particular the last two, have a bond with Shakespeare's history plays, for in these tragedies Shakespeare explores political issues that bear closely on those raised in his two tetralogies based on the internal and external conflicts of England during the fifteenth century. Thus the "Roman tragedies" may be interpreted in part as revealing Shakespeare's view of political life.
Historically, Julius Caesar was, in 60 B.C., a member of the ruling triumvirate in Rome, along with Pompey and Crassus. Crassus died in battle in 53 B.C., and in 49 B.C., in an attempt to gain absolute authority over Rome, Caesar flouted the Roman Senate by leading his forces across the Rubicon and against the armies of Pompey. In 47 B.C. at Pharsalia, Caesar defeated Pompey, then pursued him to Egypt, where Pompey was killed, and where Caesar enjoyed a dalliance with Cleopatra. The civil war continued for two more years, and when Caesar returned to Rome, he ruled with the support of the populace until his assassination in 44 B.C.
The primary source of Julius Caesar is Plutarch Lives of the Noble Grecians and Romans, translated into English by Thomas North in 1579, and the play borrows most from the essays on the lives of Brutus, Caesar, and Antony. The events covered actually took place over several years, which Shakespeare condenses into six days. As does Plutarch, Shakespeare dramatizes Caesar's physical weaknesses, but Shakespeare omits incidents from Plutarch that depict Caesar as far more dictatorial than the play suggests. Here Caesar is arrogant, but he is clearly a great man, a world conqueror, and respected by virtually all.
Yet who is the central character of the play? Some might claim that Caesar is at its heart, for he towers over the rest, and even in death holds a powerful influence. Other critics might say Brutus, who undergoes the crucial ethical quandary. Others might answer Cassius, the prime mover in the conspiracy, or Antony, who turns the conspiracy and Rome upside down.