In 180, after having ruled for 19 years, Emperor Marcus Aurelius Antoninus Augustus died while campaigning against the Germans.

Pompeianus Succeeds Marcus Aurelius as Co-RulerMarcus Aurelius had completed a stellar career, succeeding at nearly everything he attempted since his induction into the equestrian order at age six. The Emperor Hadrian seemed impressed by Aurelius' abilities and groomed him to rule: waiving requirements for entry into the priesthood and recommending that the Senate make exemption for him for the post of quaestor even though he was not 24. He was first made consul at the age of 18, and regained the position many times afterward. Upon the death of Emperor Antonius Pius in 161, Marcus Aurelius became co-ruler alongside his adopted brother Lucius Verus.

The two emperors were an odd couple. Marcus focused on the necessities of administration and carried more authority despite their political equality. Lucius, on the other hand, enjoyed the games and chariot racing. Both, however, carried an informality that endeared them to the people. They handled firsthand crises in Rome such as the flooding of the Tiber, and Lucius was dispatched to the east to battle the Parthians, who had begun an invasion. Lucius was at first accused of luxury and gambling, but he proved an able commander, and the Parthians were defeated by 167. Plague flowed through the empire after, wiping out thousands. Lucius died in 169, possibly as a casualty of the plague.

A new article by Jeff ProvineFrom 169 to 177, Marcus ruled alone. He spent his years away from Rome, campaigning against Germanic incursions across the imperial border. At age 52, he thought of the coming generation and elevated his surviving son Commodus, only sixteen years old, to co-ruler. Commodus had been born "in the purple" months after Marcus became emperor, never knowing a life outside of near-absolute authority. Commodus would be the first non-adopted son to succeed his father as emperor in generations. From the days of Vespasian, no male heirs had been born, creating a system of adoption. It arguably became a system of meritocracy, but Marcus felt that Commodus, despite his youth, would make an able ruler. Still on campaign in 180, Marcus died in Vindobona (modern day Vienna) on the Danube.

While he carried out his civic duties well, Marcus Aurelius considered himself a philosopher at heart. He had been very close with his teachers, especially Marcus Cornelius Fronto. Fronto, a Numidian-Lybian, had become famous in Rome for his oratory, believed to be next to that of the great Cicero, which spurred Antonius Pius to hire him as the tutor for Marcus and Lucius. Poor health troubled Fronto most of his adult life, ending chances at a career in politics, but instead giving him more time to write. Lucius did not appreciate the education on the level that Marcus did, who even imitated Fronto and carried out single-sided conversations with himself about the necessity of discipline. Fronto often played devil's advocate and tried to steer Marcus away from philosophy with the old saying, "Better never to have touched the teaching of philosophy .. than to have tasted it superficially, with the edge of the lips&". Another teacher, Quintus Junius Rusticus, would introduce Marcus Aurelius to Stoicism, in which he found his true calling.

In his last years of campaigning, Aurelius wrote his Meditations. While Fronto had taught him to speak, he thanked Rusticus for teaching him to think clearly. He took upon himself to be the philosopher-king, fulfilling his requirements of office while still having time to write reflections on philosophy, life, and the world. Like many Stoics, he focused on discipline and self direction, writing "If thou art pained by any external thing, it is not this that disturbs thee, but thy own judgment about it. And it is in thy power to wipe out this judgment now" (VIII. 47) and "Do not act as if thou wert going to live ten thousand years. Death hangs over thee. While thou livest, while it is in thy power, be good" (IV. 17).

None of Aurelius' reflections seemed to settle on his son Commodus, who acted a great deal like Lucius. They made an effective pair as rulers, however, with Aurelius' administrative mind while Commodus, like Lucius, held a sense of public mood. This thought settled on Aurelius, who summoned Tiberius Claudius Pompeianus, one of his best generals and the second husband of Lucius' widow, Lucilla. He had apparently offered Caesarship to Pompeianus to continue the tradition of co-rule, but Pompeianus had declined. Now Aurelius pleaded with Pompeianus to take the position should anything ever happen to Aurelius. After a great deal of convincing and a Stoic discussion of duty, Pompeianus accepted the order and the will was changed just before Aurelius' death.

Returning to Rome, Commodus seemed upset by the invasion of his rule, but Pompeianus maintained a tight grip on the young emperor. Though they bickered, the rule proved for the good: Pompeianus handling administration while Commodus won the support of the people with games and victories in the field. Pompeianus died in 195, giving rule over to Publius Helvius Pertinax, who in turn passed his title to the great general Septimius Severus. A new tradition of separation of powers continued for centuries until 406, when pressure from Hun invaders tempted German allies to revolt and flee rather than serving as the buffer Rome intended them to be. The stable empire persuaded the Germans to stay and even push back against the Huns.

Four hundred years later, another wave of invasion by Maygars and Vikings proved too much for Rome, which toppled as was carved into Viking kingdoms at sea an a Maygar empire in eastern Europe. With vast wealth behind them, the Vikings continued to explore and plunder, reaching as far as southern African, Native American, and Mayan lands.