Composition of the conspiracy
Catiline had been an unsuccessful candidate in the consular elections of the previous year (64 BC) and he did not take this lightly. The knowledge that this would be his last chance to obtain consulship led him to undertake a no-holds-barred election campaign. He had lost the support of many among the nobility in his previous campaign, which meant he had to look elsewhere to get the backing he needed. He consequently turned increasingly towards the people, and especially those plagued by debts and other difficulties. Many of the other leading conspirators had faced political problems similar to his in the Senate. Publius Cornelius Lentulus Sura, the most influential conspirator after Catiline, had held the rank of consul in 71 BC, but he had been cast out of the senate by the censors during a political purge in the following year on the pretext of debauchery. Publius Autronius Paetus 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 BC with Cicero, joined the conspiracy after he failed to obtain the consulship in 64 BC along with Catiline. By the time that the election came around, he was no longer even regarded as a viable candidate. Gaius Cornelius Cethegus, a relatively young man at the time of the conspiracy, was noted for his violent nature. His impatience for rapid political advancement may account for his involvement in the conspiracy. The ranks of the conspirators included a variety of other patricians and plebeians who had been cast out of the political system for various reasons. Many of them sought the restoration of their status as senators and their lost political power.
Promoting his policy of debt relief, Catiline initially also rallied many of the poor to his banner along with a large portion of Sulla’s veterans. Debt had never been greater than in 63 BC since the previous decades of war had led to an era of economic downturn across the Italian countryside. Numerous plebeian farmers lost their farms and were forced to move to the city, where they swelled the numbers of the urban poor. Sulla's veterans were in bad economic straits as well. Desiring to regain their fortunes, they were prepared to march to war under the banner of the "next" Sulla. Thus, many of the plebs eagerly flocked to Catiline and supported him in the hope of the absolution of their debts.