The Eternal City
Commodus seceded his father as Emperor in 180AD. He was not a fan of war and negotiated with the Germanic tribes in order to return to Rome. This would lead to discontent among the soldiers and generals. He was equally disinterested in actually running the Empire and preferred to defer to advisors many of them freedman.
In our campaign his reign was cut short in 182 as conspirators sought to kill the Emperor leading to a brief period of civil war. For what occurred historically check out
this wiki link