Imperium, by Robert Harris, is a historical novel set during the late Roman Republic and narrated by Cicero’s enslaved secretary Tiro as he looks back from extreme old age on the orator and statesman’s climb to the consulship. Set between 79 and 64 BCE, the book follows a provincial “new man” with no fortune and no army through the courts, the Senate, and the streets, tracking three intertwined concerns: The Corrupting Price of Ambition, Eloquence as Political Weapon, and The Republic’s Slow Surrender to Strongmen. Tiro’s narration moves between the events as they unfolded and the perspective of his very old age, when Cicero is long dead, and the Republic itself has given way to empire. Harris draws on Cicero’s surviving speeches and letters to bring Roman politics to life while inventing for Tiro a documentary intimacy with his subject that the historical record does not provide.

This guide refers to the 2006 paperback edition published by Pocket Books.

Content Warning: The source material and guide feature depictions of graphic violence, death, death by suicide, gender discrimination, racism, substance use, and sexual content.

Plot Summary

The narrator is Tiro, an enslaved (later freed) household secretary who served Marcus Tullius Cicero for decades and invented a shorthand system to record the famous orator’s words. Writing as a very old man, Tiro promises a truthful account of how a sickly provincial advocate from Arpinum made himself master of Rome through speech alone.

The main narrative opens with Cicero in his late twenties, traveling east with Tiro to study oratory. Under the rhetorician Apollonius Molon in Rhodes, Cicero strengthens his weak voice and corrects his stutter; Molon predicts that he will conquer Rome. Back in Italy, Cicero marries the wealthy, sharp Terentia to meet the Senate’s property qualification, serves as quaestor in Sicily, and is humiliated on the way home when fashionable society at Puteoli cannot recall what he has been doing. He resolves to live thereafter in constant public view in Rome.

Six years later, a Sicilian friend named Sthenius arrives at Cicero’s door. The governor of Sicily, Gaius Verres, has stolen Sthenius’s art collection, framed him on a forgery charge, and now intends to try him in absentia on a capital count and crucify him. Cicero raises the matter in the Senate, where Verres’s advocate, Hortensius, and his aristocratic allies filibuster him. Verres convicts Sthenius and sends men to arrest him, but Cicero hides Sthenius in a tenement owned by Terentia and turns to the tribunes, representatives of the common Romans whose power extends to shielding individuals from unjust magistrates.

Through the tribune Palicanus, an ally of the popular general Pompey, Cicero is drawn into Pompey’s faction; Pompey hopes to assume the role of consul, Rome’s highest elected office, though he is too young for it. He addresses the tribunes’ assembly, attacks senatorial corruption, and wins a unanimous vote sparing Sthenius. Pompey returns from Spain just as his great rival, General Crassus, is crushing a rebellion of enslaved workers led by a man named Spartacus. Journeying to meet Crassus, Cicero encounters 6,000 captured followers of Spartacus, whom Crassus has crucified along the Appian Way, the primary road into Rome. Summoned to Crassus’s tent, Cicero refuses to sell Tiro and then refuses to back Crassus’s triumph, a victory procession for a conquering general. Later, he supports a triumph for Pompey, hoping to curry favor and secure his own aedileship, an office in which he would oversee functions like the distribution of grain and the organization of public ceremonies. In secret, however, Pompey and Crassus reach an agreement to serve jointly as consuls, and Verres is recalled from Sicily.

Though Cicero previously declined to take Sthenius’s case directly, this changes when Sthenius returns with two more victims and crates of evidence of Verres’s thefts, judicial murders, and extortions. Cicero announces that he will run for aedile and prosecute Verres for extortion. Hortensius schemes to install a rival prosecutor more concerned with his personal vendetta against Verres than with exposing him publicly, but Cicero wins the right to bring the case and is granted 110 days in Sicily to gather evidence.

In Sicily, Cicero and his small party tour the province collecting depositions. At Messana, they learn that Verres recently flogged and crucified a Roman citizen, Publius Gavius, on the shore facing Italy. The new governor, Lucius Metellus, tries to intimidate witnesses, but Cicero seizes tax-collector records and uncovers bribes redeposited under the alias “Verrucius.” He leaves the island with crates of documents and a list of witnesses.

Back in Rome, Hortensius runs a decoy extortion trial to clog the court calendar until the sympathetic Marcus Metellus (Lucius’s brother) will take over as judge; he also engineers a jury packed with hostile aristocrats. However, Cicero wins the aedileship despite Verres’s bribery, and when the trial opens in August, he abandons the customary long opening speech and immediately calls his 100 Sicilian witnesses one after another, completing the case in days rather than months. Verres flees Rome before the verdict. Pompey, who ensured that the judge would permit Cicero’s unorthodox courtroom strategy, personally instructs Cicero to accept a settlement of 1.5 million sesterces, and Cicero complies.

As aedile, Cicero keeps grain prices low, builds a precinct organization, and stages the Festival of Ceres. Two years after the Verres trial, Cicero defends a former governor of Further Gaul, Fonteius, against extortion charges and wins; his cousin Lucius, disgusted at the betrayal of provincial victims, dies the same day, likely by suicide. Cicero brings Lucius’s ashes to the family estate at Arpinum, where news arrives that pirates have burned the consular fleet at Ostia and kidnapped two praetors.

Pompey summons Cicero to his estate, where the young Julius Caesar, recently returned from Spain, is also present. Pompey unveils a scheme for a single supreme commander—Pompey himself—over the entire Mediterranean for three years. Cicero advises that Pompey’s name be omitted from the bill, which would mark an unprecedented concentration of power in one individual. Meanwhile, the tribunes Gabinius and Cornelius stoke public panic about the pirates as aristocratic opposition to the proposal hardens; Crassus bribes tribunes to veto the bill, known as the lex Gabinia.

Crassus offers Cicero a finer house and support for the consulship if he will back a shared command rather than one given to Pompey alone. Cicero refuses, and Crassus invokes the murdered populist tribune Tiberius Gracchus as a warning. Cicero sends Tiro to the archive to research how Gracchus once removed an obstructing tribune by tribal vote and then proposes the same tactic against Crassus’s tribune Trebellius. On voting day, after 17 tribes vote to strip Trebellius of office, the veto collapses, the lex Gabinia passes, and Pompey accepts the command and leaves Rome.

Cicero tops the praetorian poll the next year and draws the extortion court. Pompey ultimately destroyed the pirates in just 49 days, and the new tribune Manilius proposes transferring command of a war against King Mithradates (in modern-day Turkey) from Lucullus to Pompey. Pressed by Pompey, Cicero delivers his first speech from the rostra in support of the lex Manilia, and the bill passes.

Cicero waives his post-praetorian province to remain in Rome. However, his plans to run for consul encounter an obstacle when the corrupt Sergius Catilina is barred from running during the current year because he is being prosecuted for extortion in Africa. Unwilling to square off against Catilina in the consular election the following year, Cicero considers defending Catilina to place him in his debt. However, when he meets with Catilina, he is disgusted to find him in league with Clodius; the jury has already been bribed. He refuses to play the part of Catilina’s attorney, and Catilina declares enmity before being acquitted.

On a long canvassing tour of Nearer Gaul, Cicero campaigns on extending the franchise across the Po. However, Governor Piso warns him that the aristocrats will rally behind a disreputable but noble-born candidate named Antonius Hybrida, leaving Cicero and Catilina to fight for second place. A wealthy friend later reports gossip from aristocratic dinners, informing Cicero that Hybrida and Catilina are running on a joint ticket and that Crassus is financing the entire slate; Cicero believes that Caesar is likely behind him.

Cicero baits a bribery agent named Salinator, who confesses Crassus’s role and names the candidates being purchased: two consuls, 10 tribunes, and a slate of praetors including Lentulus Sura. The young apprentice Caelius Rufus, who lives in Crassus’s house, reveals a hidden listening alcove in Crassus’s meeting room. Tiro hides there and takes shorthand notes through a long conference of the conspirators. The plot has four stages: sweep the elections, push through a land-redistribution bill, install 10 commissioners with sweeping powers under Crassus and Caesar, and annex Egypt the following summer.

Cicero and Tiro spend the night transcribing and decoding the notes, and Cicero sends a copy to Hortensius. In the Senate, he denounces Mucius as bought, attacks Hybrida and Catilina, and stares at Crassus without naming him. That night, Hortensius’s carriage takes Cicero to Lucullus’s villa outside the city, where several aristocrats are waiting.

At the Field of Mars the next day, Hortensius publicly raises Cicero’s arm in the candidates’ enclosure, signaling aristocratic support. Cicero is ultimately elected consul unanimously across all 193 centuries, with Hybrida as his colleague. At dinner that night, Cicero reveals the price of victory: He has promised the aristocrats that he will oppose the land-reform bill and propose triumphs for Lucullus and another general. Later, alone with Tiro, Cicero muses on how history will remember him.