Answer
The Senatorial Revolt caused the Year of the Six Emperors. This was a revolt by senators against Emperor Pertinax. The senators were unhappy with Pertinax's reforms and they felt that he was too close to the common people. They assassinated Pertinax and proclaimed the Praetorian prefect Didius Julianus as emperor. This led to a series of coups and assassinations, which resulted in the Year of the Six Emperors.