structural:scholar_edition
Death and succession (180)

Marcus Aurelius died at the age of 58 on 17 March 180 of unknown causes in his military quarters either in the city of Vindobona (province of Pannonia Superior, today Vienna) or near Sirmium (province of Pannonia Inferior, modern Sremska Mitrovica). He was immediately deified and his ashes were returned to Rome, where they rested in Hadrian's mausoleum (modern Castel Sant'Angelo) until the Visigoth sack of the city in 410. His campaigns against Germans and Sarmatians were also commemorated by a column and a temple built in Rome. Some scholars consider his death to be the end of the Pax Romana.

Marcus was succeeded by his son Commodus, whom he had named Caesar in 166 and with whom he had jointly ruled since 177. Biological sons of the emperor, if there were any, were considered heirs; however, it was only the second time that a "non-adoptive" son had succeeded his father, the only other having been a century earlier when Vespasian was succeeded by his son Titus. Historians have criticized the succession to Commodus, citing Commodus's erratic behaviour and lack of political and military acumen. At the end of his history of Marcus's reign, Cassius Dio wrote an encomium to the emperor, and described the transition to Commodus in his own lifetime with sorrow:

did not meet with the good fortune that he deserved, for he was not strong in body and was involved in a multitude of troubles throughout practically his entire reign. But for my part, I admire him all the more for this very reason, that amid unusual and extraordinary difficulties he both survived himself and preserved the empire. Just one thing prevented him from being completely happy, namely, that after rearing and educating his son in the best possible way he was vastly disappointed in him. This matter must be our next topic; for our history now descends from a kingdom of gold to one of iron and rust, as affairs did for the Romans of that day.

Dio adds that from Marcus's first days as counsellor to Antoninus to his final days as emperor of Rome, "he remained the same and did not change in the least."

Michael Grant, in The Climax of Rome, writes of Commodus:

The youth turned out to be very erratic, or at least so anti-traditional that disaster was inevitable. But whether or not Marcus ought to have known this to be so, the rejections of his son's claims in favour of someone else would almost certainly have involved one of the civil wars which were to proliferate so disastrously around future successions.