Calpurnia was either the third or the fourth wife of Caesar, and the one to whom he was married at the time of his assassination. According to contemporary sources, she was a good and faithful wife, in spite of her husband's infidelity; and, forewarned of the attempt on his life, she endeavoured in vain to prevent his murder.
Born c. 76 BC, Calpurnia was the daughter of Lucius Calpurnius Piso Caesoninus, consul in 58 BC. Her brother was Lucius Calpurnius Piso, who would become consul in 15 BC. Prior to their marriage, Caesar had been married either two or three times.
In his childhood, Caesar had been betrothed to Cossutia, the daughter of a wealthy eques, although there is some uncertainty as to whether they were ever formally married. According to Suetonius, he was obliged to break off their engagement when, at the age of sixteen, he was nominated Flamen Dialis, a high-ranking priestly office whose holders had to be married by confarreatio, an ancient and solemn form of marriage that was open only to patricians.
Caesar then married Cornelia, a woman of patrician rank, and the daughter of Lucius Cornelius Cinna, at that time the most powerful man in Rome. By all accounts, their marriage was a happy one, and the product of their union was Julia, Caesar's only legitimate child. Following the downfall and death of Cinna and the ruin of his faction, the dictator Sulla commanded Caesar to divorce his rival's daughter, a demand that Caesar refused at great personal risk, for it nearly cost him his life. Cornelia died in 69 or 68 BC, as her husband was preparing to set out for Spain.
On his return, Caesar married Pompeia, a granddaughter of Sulla. Their marriage ended in scandal. In 63 BC, Caesar had been elected Pontifex Maximus, receiving as his official residence a house on the Via Sacra. Here the sacred rites of the Bona Dea, from which all men were excluded, were celebrated in the winter of 62. But an ambitious young nobleman named Publius Claudius Pulcher entered the house disguised as a woman, ostensibly for the purpose of seducing Pompeia. His subsequent discovery shocked the Roman aristocracy, and rumours swirled about Pompeia's fidelity. Caesar felt that he had no choice but to divorce Pompeia, not because he personally believed the rumours, but because the wife of the Pontifex Maximus had to be above suspicion.
Calpurnia married Caesar late in 59 BC, during the latter's consulship. She was about seventeen years old, and Caesar's daughter, Julia, was likely older than her stepmother. About this time, Julia married Gnaeus Pompeius Magnus, a former protégé of Sulla, who had been consul in 70 BC, and recently become one of Caesar's closest political allies.
Calpurnia's contemporaries describe Calpurnia as a humble, often shy woman. She seems to have tolerated Caesar's affairs; he was rumoured to have seduced the wives of a number of prominent men, including both of his allies in the First Triumvirate; he had for some time been intimate with Servilia, a relationship that was an open secret at Rome. It was rumoured that Caesar was the father of Servilia's son, Marcus Junius Brutus, although this is improbable on chronological grounds,, and that Servilia attempted to interest Caesar in her daughter, Junia Tertia—who according to other rumours, was also Caesar's daughter. Caesar also carried on affairs with the Mauretanian queen, Eunoë, and most famously, with Cleopatra, the Queen of Egypt, who claimed that he was the father of her son, Ptolemy XV, better known as "Caesarion". By all accounts Calpurnia was a faithful and virtuous wife, but no children resulted from her marriage to Caesar.
According to the Roman historians, Caesar's murder was foretold by a number of ill omens, as well as the Etruscan haruspex Spurinna, who warned him of great personal danger either on or by the Ides of March in 44 BC. The night before his assassination, Calpurnia dreamed that Caesar had been stabbed, and lay dying in her arms. In the morning, she begged him not to meet the senate, as he had planned, and moved by her distress and entreaties, he resolved not to go. But Decimus Junius Brutus, one of Caesar's closest friends, whom he had recently appointed Praetor Peregrinus, and secretly one of the conspirators against him, came to the house and persuaded Caesar to ignore the omens, and go to the senate.
Following her husband's assassination, Calpurnia delivered all of Caesar's personal papers, including his will and notes, along with his most precious possessions, to the consul Marcus Antonius, one of Caesar's most trusted allies, who had not been involved in the conspiracy. She never remarried.
- In Shakespeare's Julius Caesar, Calpurnia has a dream that a statue of Caesar was flowing with blood as many Romans wash their hands in the blood. She also sees in her dream that Julius Caesar would die in her arms.
- Calpurnia was portrayed by Gertrude Michael in Cleopatra (1934), Greer Garson in the 1953 adaptation of Shakespeare's Julius Caesar, Gwen Watford in Cleopatra (1963), Joan Sims in Carry On Cleo (1964), Jill Bennett in the 1970 adaptation of Julius Caesar and Valeria Golino in the 2002 miniseries Julius Caesar.
- Calpurnia was shown solving a murder in Mist of Prophecies (2002) - part of the Roma Sub Rosa series by Steven Saylor. She gets Gordianus the Finder to look into a threat to her husband in a later book in this series, The Triumph of Caesar (2008). She is portrayed as a woman of formidable intelligence and efficiency, utterly devoted to her husband's interests, but with an incongruous fascination with trying to foretell the future.
- Calpurnia was portrayed by Haydn Gwynne in HBO's series Rome. She is depicted as proud and traditional, and having had a vision of Caesar's death.
- Shakespeare's Calpurnia was portrayed by Sylvia Lennick in Wayne and Shuster's comedy sketch "Rinse the Blood Off My Toga", parodied as a hysterical Italian-American housewife, repeatedly wailing "I told him, Julie! Don't go!" in a Bronx accent.