Commodus was Roman Emperor
Roman Emperor
The Roman emperor was the ruler of the Roman State during the imperial period . The Romans had no single term for the office although at any given time, a given title was associated with the emperor...

 from 180 to 192. He also ruled as co-emperor with his father Marcus Aurelius from 177 until his father's death in 180. His name changed throughout his reign; see changes of name for earlier and later forms. His accession as emperor was the first time a son had succeeded his father since Titus
Titus , was Roman Emperor from 79 to 81. A member of the Flavian dynasty, Titus succeeded his father Vespasian upon his death, thus becoming the first Roman Emperor to come to the throne after his own father....

 succeeded Vespasian
Vespasian , was Roman Emperor from 69 AD to 79 AD. Vespasian was the founder of the Flavian dynasty, which ruled the Empire for a quarter century. Vespasian was descended from a family of equestrians, who rose into the senatorial rank under the Emperors of the Julio-Claudian dynasty...

 in 79.

176    Emperor Marcus Aurelius grant his son Commodus the rank of ''Imperator'' and makes him Supreme Commander of the Roman legions.

180    Marcus Aurelius dies leaving Commodus the sole emperor of the Roman Empire.

193    The Senate chooses Pertinax against his will to succeed Commodus as Roman Emperor.