Commodus

The accession of Commodus in 180 broke with eight decades of practice in which emperors had reached the throne by adoption. Born in 161 at Lanuvium, a son of Marcus Aurelius and Faustina the Younger, he was the first emperor in over a century to succeed his natural father, having been named Caesar in 166 and co-Augustus in 177 while still a teenager.

On Marcus's death during the Danubian wars, Commodus concluded peace with the Marcomanni and Quadi and returned to Rome, abandoning any plan of annexation beyond the Danube. The decision was criticized by senatorial writers but gave the frontier a period of relative stability. At Rome, however, his reign was punctuated by conspiracies, beginning with one involving his sister Lucilla in 182, after which he withdrew increasingly from administration. Government passed to a succession of favorites — the praetorian prefect Perennis, killed in 185, and the freedman Cleander, sacrificed to a rioting populace in 190.

In his final years Commodus's self-presentation grew extravagant. He identified himself with Hercules, accepted extraordinary titles, renamed the months and styled Rome a colony bearing his name, and appeared in the amphitheater as a beast-hunter and gladiator. For these years the historian Cassius Dio was an eyewitness senator; his account is hostile but contemporary, and the broad outline of the emperor's arena appearances and divine pretensions is generally accepted, even if individual anecdotes invite caution.

On the last day of 192 he was murdered in a palace conspiracy involving the prefect Laetus, the chamberlain Eclectus and his mistress Marcia. The Senate decreed the erasure of his memory, and his death opened the civil wars of 193. The sequel ties him to the next dynasty: Septimius Severus, victorious in those wars, had himself retroactively declared an adopted son of Marcus Aurelius, restored Commodus's memory and deified him as his "brother." Thus the founder of the Severan line grafted his house onto the Antonine family that Commodus's death had extinguished.