Marcus Tullius Tiro, Cicero's secretary, invents the so-called Tironian Notes, a shorthand system for the purpose of rapid transcription, in 63 BCE.

Caesar also writes in shorthand, a craft practiced widely among Roman writers.

In this year, Caesar prosecutes Gaius Rabirius, a now-elderly senator who had been involved in the death of Lucius Appuleius Saturninus thirty-seven years earlier.

Caesar puts up Titus Labienus (whose uncle had lost his life among the followers of Saturninus on that occasion) to accuse Rabirius of having been implicated in the murder.

Caesar's real object is to attack the legality of the Senatus consultum ultimum, the Senate's decree of a state of emergency, and thus to warn the Senate against interference by force with popular movements, to uphold the sovereignty of the people and the inviolability of the person of the tribunes, at the time of the conspiracy of Lucius Sergius Catilina.

The obsolete accusation of perduellio, the term for the capital offense of high treason, is revived, and the case is heard before Caesar and his cousin Lucius Julius Caesar as commissioners specially appointed (duoviri perduellionis).

Rabirius is condemned, and the people, to whom the accused has exercised the right of appeal, are on the point of ratifying the decision, when the praetor Quintus Caecilius Metellus Celer pulls down the military flag from the Janiculum, which is equivalent to the dissolution of the assembly.

Caesar's object having been attained, the matter is now allowed to drop.

The defense is taken by Cicero, consul at the time; the speech is extant: Pro Rabirio reo perduellionis.

Catiline chooses to stand for the consulship again in the following year, but by the time of the consular election for 62 BCE, he has lost much of the political support he had enjoyed during the previous year's election.

He is defeated by two other candidates, Decimus Junius Silanus and Lucius Licinius Murena, ultimately crushing his political ambitions.

The only remaining chance of attaining the consulship are through an illegitimate means, conspiracy or revolution.

Catiline begins to attach many other men of senatorial and equestrian rank to his conspiracy, and like him many of the other leading conspirators have faced similar political problems in the Senate.

Publius Cornelius Lentulus Sura, the most influential conspirator after Catiline, had held the rank of consul in 71 BCE, but during a political purge in the following year had been cast out of the senate by the censors on the pretext of debauchery.

Autronius was also complicit in their plot, since he was banned from holding office in the Roman government.

Another leading conspirator, Lucius Cassius Longinus, who was praetor in 66 BCE with Cicero, had joined Catiline’s conspiracy after he failed to obtain the consulship in 64 BCE along with Catiline.

By the time that the election came around, he was no longer even regarded as a viable candidate.

Gaius Cethegus, a relatively young man at the time of the conspiracy, is noted for his violent nature; his impatience for rapid political advancement may account for his involvement in the conspiracy.

The ranks of the conspirators include a variety of other patricians and plebeians who had been cast out of the political system for various reasons.

Many of them seek the restoration of their status as senators and their lost political power.

Catiline, promoting his policy of debt relief, initially also rallies many of the poor to his banner along with a large portion of Sulla’s veterans.

As the previous decades of war have led to an era of economic downturn across the Italian countryside, debt has never been greater than in 63 BCE.

Numerous plebeian farmers have lost their farms and are forced to move to the city, where they swell the numbers of the urban poor.

Sulla's veterans have spent and squandered the wealth they had acquired from their years of service.

Desiring to regain their fortunes, they are prepared to march to war under the banner of the "next" Sulla.

Thus, many of the plebs eagerly flock to Catiline and support him in the hope of the absolution of their debts.

Catiline sends Gaius Manlius, a centurion from Sulla’s old army, to manage the conspiracy in Etruria where he assembles an army.

Other men are sent to take other important locations throughout Italy, and even a small slave revolt begins in Capua.

While civil unrest is felt throughout the countryside, Catiline makes the final preparations for the conspiracy in Rome.

Their plans include arson and the murder of a large portion of the senators, after which they will join up with Manlius’ army.

Finally, they will return to Rome and take control of the government.

To set the plan in motion, Gaius Cornelius and Lucius Vargunteius are to assassinate Cicero early in the morning on November 7, 63 BCE, but Quintus Curius, a senator, who will eventually become one of Cicero's chief informants, warns Cicero of the threat through his mistress Fulvia.

Fortunately for Cicero, he escapes death that morning by placing guards at the entrance of his house who scare the conspirators away.

On the following day, Cicero convenes the Senate in the Temple of Jupiter Stator and surrounds it with armed guards.

Much to Cicero's surprise, Catiline is in attendance while he denounces him before the Senate; however, the senators adjacent to Catiline slowly move away from him during the course of the speech, the first of Cicero's four Catiline Orations.

Catiline, incensed at these accusations, exhorts the Senate to recall the history of his family and how it had served the republic, instructing them not to believe false rumors and to trust the name of his family.

He finally accuses them of placing their faith in a "homo novus", Cicero, over a "nobilis", himself.

Supposedly, Catiline violently concluded that he would put out his own fire with the general destruction of all.

He rushes home immediately afterward and the same night ostensibly complies with Cicero's demand and flees Rome under the pretext that he is going into voluntary exile at Massilia because of his "mistreatment" by the consul; however, he arrives at Manlius’ camp in Etruria to further his designs of revolution.

Caesar, running in 63 BCE for election to the post of Pontifex Maximus, chief priest of the Roman state religion, had run against two powerful senators, with accusations of bribery by all sides.

Caesar had won comfortably, despite his opponents' greater experience and standing.

When Cicero, who is consul this year, exposes Catiline's conspiracy to seize control of the republic, several senators accuse Caesar of involvement in the plot.