[11] After a complex political realignment, Octavian – Caesar's adopted son – made himself consul and, with his colleague, passed a law retroactively making Brutus and the other conspirators murderers.

[34] Vettius was detained for admitting possession of a weapon within the city, and quickly changed this story the next day, dropping Brutus' name from his accusations.

[35] Brutus' first appearance in public life was as an assistant to Cato, when the latter was appointed by the senate acting at the bequest of Publius Clodius Pulcher, as governor of Cyprus in 58.

In 50, he – with Pompey and Hortensius – played a significant role in defending Brutus' father-in-law Appius Claudius from charges of treason and electoral malpractice.

[63] Caesar appointed Brutus as governor (likely as legatus pro praetore) for Cisalpine Gaul while he left for Africa in pursuit of Cato and Metellus Scipio.

[65] After Caesar's last battle against the republican remnant in March 45, Brutus divorced his wife Claudia in June and promptly remarried his cousin Porcia, Cato's daughter, late in the same month.

Plutarch, Appian, and Cassius Dio, all writing in the imperial period, focused on peer pressure and Brutus' perceived philosophical duty to his country and his family's reputation.

[83] Various plans were proposed – an ambush on the via sacra, an attack at the elections, or killing at a gladiator match – eventually, however, the conspiracy settled on a senate meeting on the Ides of March.

[86] The specific details of the assassination vary between authors: Nicolaus of Damascus reports some eighty conspirators, Appian only listed fifteen, the number of wounds on Caesar ranges from twenty-three to thirty-five.

[92] The conspirators travelled to the Capitoline Hill; Caesar's deputy in the dictatorship, Marcus Aemilius Lepidus, moved a legion of troops from the Tiber Island into the city and surrounded the forum.

[93] Suetonius reports that Brutus and Cassius initially planned to seize Caesar's property and revoke his decrees, but stalled out of fear of Lepidus and Antony.

Publius Cornelius Dolabella, who was to become consul in a few days on the 18th, decided immediately to assume the consulship illegally, expressed his support of Brutus and Cassius before the people, and joined the liberatores on the Capitoline.

[96] Some of the supposed prodigies did in fact occur, but were actually unrelated to Caesar's death: Cicero's statue was knocked over but only in the next year, Mt Etna in Sicily did erupt but not contemporaneously, a comet was seen in the sky but only months later.

[97] While the Caesarians had troops near the capital at hand, the liberatores were soon to assume control of vast provincial holdings in the east which would provide them, within the year, with large armies and resources.

[98] Seeing that the military situation was initially problematic, the liberatores decided then to ratify Caesar's decrees so that they could hold on to their magistracies and provincial assignments to protect themselves and rebuild the republican front.

Various ancient sources report that the crowd set the senate house on fire and started a witch-hunt for the tyrannicides, but these may have been spurious embellishments added by Livy, according to T P Wiseman.

Brutus, as urban praetor in charge of the city's courts, was able to get a special dispensation to leave the capital for more than 10 days, and he withdrew to one of his estates in Lanuvium, 20 miles south-east of Rome.

[105] Dolabella at this time was on the side of the liberatores and also was the only consul at Rome; Antony's brother Lucius Antonius helped Octavian to announce publicly that he was to fulfil the conditions of Caesar's will,[106] handing an enormous amount of wealth to the citizenry.

Brutus also wrote a number of speeches disseminated to the public defending his actions, emphasising how Caesar had invaded Rome, killed prominent citizens, and suppressed the popular sovereignty of the people.

[120] Cicero's policy of attempting to unify Octavian with the senate against Antony and Lepidus started to fail in May; he requested Brutus to take his forces and march to his aid in Italy in mid-June.

[122] Shortly afterwards, Octavian and his colleague, Quintus Pedius, passed the lex Pedia making the murder of a dictator retroactively illegal, and convicting Brutus and the assassins in absentia.

[125] When news of the triumvirate and their proscriptions reached Brutus in the east, he marched across the Hellespont into Macedonia to quell rebellion and conquered a number of cities in Thrace.

[133] The Caesarians also marched into Greece, evading the naval patrols of Sextus Pompey, Lucius Staius Murcus [de], and Gnaeus Domitius Ahenobarbus.

[140] Fearful of defections among his troops and the possibility of Antony cutting his supply lines, Brutus joined battle after attempting for some time to continue the original strategy of starving the enemy out.

[147] Even when he was still alive, Brutus' literary output, especially the pamphlets of 52 BC against Pompey's dictatorship (De dictatura Pompei) and in support of Milo (Pro T. Annio Milone) coloured him as philosophically consistent, and motivated only by principle.

[71] Some high imperial writers also admired his rhetorical skills, especially Pliny the Younger and Tacitus, with the latter writing, "in my opinion, Brutus alone among them laid bare the convictions of his heart frankly and ingeniously, with neither ill-will nor spite".

[148] In the 12th century, English writer John of Salisbury, who owned a copy of De Officis, emulated Cicero’s beliefs by defending tyrannicide as a moral obligation.

[158][159] Dante Alighieri's Inferno notably placed Brutus in the lowest circle of Hell for his betrayal of Caesar, where he (along with Cassius and Judas Iscariot) is personally tortured by Satan.

Dante's views gave a further theological bent as well: by killing Caesar, Brutus "was resisting God's 'historical design'": the development of the Roman Empire with its fusion with Christianity and the Christianised monarchies of his day.

[162] Brutus was also present in the arts during the early modern period, particularly in Shakespeare's Julius Caesar, which depicted him "more of a troubled soul than a public symbol... [and] often sympathetic".