Following the princeps murder on January 24, 794, by conspirators composed primarily of Roman Noblemen and Senators, Consul Sentius Saturninus assumed the position of head of state in the capital, guiding the senate to power on the back of a military comprised of both Auxiliaries and Praetorian Guardsmen.
However, few generals/proconsuls/governors accepted the senates usurpation of power in the imperial capital, and in lieu of a clear successor to the principate, some began to push their claim; whether it was artificial or not. These pretenders were;
- Lucius Domitius Ahenobarbus - Son of Caligula's brother-in-law Gnaeus Domitius Ahenobarbus;
- Gnaeus Domitius Corbulo - Caligula's brother-in-law through the emperor's marriage to Corbulo's half-sister Milonia Caesonia;
- Aulus Plautius - Relative to Caligula's uncle's first wife, Plautia Urgulanilla and military governor of the province of Pannonia;
- Publius Petronius - Caligula's appointed governor of Syria, and husband of Aulus Plautius' sister, Plauta Plautius.
Assassination of Caligula
In 794, a conspiracy involving many Roman noblemen and senators against the then incumbent emperor Germanicus (Caligula) ended with his assassination on January 24. Whilst the original plot called for simply the head of the princeps, it soon became apparent the soldiers loyal to the senatorial conspirators were ordered to kill the entirety of the royal family. With the assassination of Tiberius Claudius Nero Germanicus (Germanicus' uncle and heir) shortly after the emperor's death, the nation was left with no clear successor. The consul of the Roman Senate, Gnaeus Sentius Saturninus soon took power after hearing the news of both Germanicus' and Tiberus' deaths, convened a meeting with a number of senators and praetorian guardsmen involved in the plot, almost all of which pledged their allegiance to both him, and the restored republic. Pomponius Secundus was subsequently chosen by the senate as the second consul whilst the guardsmen loyal to Saturninus consolidated control over the capital.
However, outside the city of Rome, the new government found little popularity, as most legions and governors soon pledged their allegiance to a number of different successors, the two most prominent being Domitius Ahenobarbus and Domitius Corbulo, the earlier being three years of age at the time, the latter being almost three decades older;, and yet despite his age, most governors pledge to support Ahenobarbus' claim, expecting greater rewards than if they supported Corbulo. In mid-March, the then governor of the province of Pannonia, Aulus Plautius decided against supporting either pretenders, and instead raised the Legio IX Hispana, Legio XI Claudia, Legio XV Apollinaris, and the Legio VII Claudia in support of his own claim on the principate (claiming legitimacy through his distant relative, Plautia Urgulanilla, Emperor Germanicus' aunt).
Reign of Aemilius
By late-March, Plautius' legions had began making their way down the Italian peninsula unhindered by the Imperial military, or legions faithful to the new government in Rome, which was slow becoming less and less popular among the people in the capital, and around the empire. In early-April, news began to spread of a conspiracy in the Senate itself against Saturninus who's power with the city's guard, and Praetorian Guardsmen, was slowly getting more powerful. By mid-April, the co-consul to Saturninus, Pomponius Secundus managed to get in contact with Plautius, who by now was poised outside of Rome waiting to attack and break the city's defences. The pretender was made aware of the plot within the Senate surrounding a future assassination of the head consul Saturninus, and as one of the heads of the conspiracy, Secundus struck a deal with Plautius; if the Senate was to deal with Saturninus and murder him, Plautius would be given clear entry into the city as Emperor, and Secundus would become the next consul. The proposal was accepted.On May 2, Saturninus came to the floor of the Senate to make a speech on the status of the city (and his own personal) guard, who on that day were away from Curia Julia were the Senate meetings were held. Towards the end of his time on the floor, Secundus, stepped down from his chair, alongside fourteen other senators, and swarmed Saturninus as he attempted to call his guard to his aid. The consul was stabbed 30 times before he stopped moving, and immediately, the Senate members of the conspiracy swore allegiance to Secundus. In the afternoon, Pomponius gained control of the Praetorian Guard loyal to the position of Emperor, and with their support, he followed through on his deal with Plautius, giving him entrance into the capital. Shortly after, the senate declared the pretender as Augustus as he took the imperial name Aemilius Julius Caesar Augustus Germanicus.