The so-called first Catilinarian conspiracy was an almost certainly fictitious conspiracy in the late Roman Republic. According to various ancient tellings, it involved Publius Autronius Paetus, Publius Cornelius Sulla, Lucius Sergius Catilina, and others. Ancient accounts of the alleged conspiracy differ in the participants; in some tellings, Catiline is nowhere mentioned. Autronius and Sulla had been elected consuls for 65 BC but were removed after convictions for bribery. New consuls were then elected. The supposed goal of the conspiracy was to murder the second set of consuls elected for 65 BC and, in their resulting absence, replace them.
Almost all modern historians believe the conspiracy is fictitious and dismiss claims thereof as merely slanderous political rumours. The core of the legend, a plot by the two consuls-elect for 65 BC to kill and usurp the consuls, is dismissed as inconceivable. The participation of others, such as Catiline, is rejected as inconsistent with their immediately following political actions; most claims of participation are believed to be discrediting retrojections introduced in the aftermath of the real Catilinarian conspiracy in 63 BC.