The History of Rome

Carcalla was killed by his Praetorian Prefect Macrinus in 217 AD. Macrinus then spent a troubled year as Emperor before the House of Severus came back to challenge his rule.

Septimius Severus died in 211 while campaigning in Britain. He left the Empire to his sons, but their mutual hatred for one another meant that one of them was going to wind up dead.

After defeating Clodius Albinus, Septimius Severus turned over daily administration of the Empire to his Praetorian Prefect Gaius Plautianus, while the Emperor himself went looking for further military vicotries in Parthia.  

Septimius Severus became the undisputed Emperor of Rome after defeating Pescennius Niger in 194 and Clodius Albinus in 197.

After buying the Imperial throne, Didius Julianus only remained in power for 66 days before being ousted by Septimius Severus.

After Commodus was assassinated, Pertinax reigned for 86 days. He was murdered by the Praetorian Guard in March 193 and the Imperial throne was auctioned off the highest bidder.

Commodus went off the deep end around 190 AD and was finally killed by his inner circle in 192.

The reign of Commodus turned on a botched assassination attempt orchestrated by his sister in 182 AD.

Marcus elevated Commodus to the position of co-Emperor and then died a few years later while campaigning in the north.

In 175 Avidius Cassius led a brief revolt in the east that forced Marcus to postpone his final triumph along the Danube.