When the behavior of Commodus turned increasingly erratic during the early 190s, Laetus is thought to have been implicated in the conspiracy that led to the emperor's murder on December 31, 192. The plot was a calculated attempt to advance the city prefect Publius Helvius Pertinax to the throne, but the assassination inadvertently initiated a period of civil war known as the Year of the Five Emperors, during which the Roman Empire witnessed five different claimants to the imperial power. The year opened with the brief reigns of Pertinax and Didius Julianus, before erupting to a full-scale war between the generals Pescennius Niger, Clodius Albinus and Septimius Severus.