Antoninus Pius prepares for a new war against the Parthian Empire, ruled by Vologases IV, in 155.

The war, sparked, as usual, by a dispute over the kingdom of Armenia, is brief and results in an inconclusive peace.

Parthian king Vologases IV enters the Kingdom of Armenia (a Roman client state) in the late summer autumn of 161, expels its king and installs his own—Pacorus, an Arsacid like himself.

At the time of the invasion, the governor of Syria is L. Attidius Cornelianus, who had been retained as governor even though his term ended in 161, presumably to avoid giving the Parthians the chance to wrong-foot his replacement.

The governor of Cappadocia, the front-line in all Armenian conflicts, is Marcus Sedatius Severianus, a Gaul with much experience in military matters.

Persuaded by Alexander of Abonutichus, a prophet who carries a snake named Glycon around with him, that he can defeat the Parthians easily, and win glory for himself, Severianus leads a legion (perhaps the IX Hispana) into Armenia, but is trapped by the great Parthian general Chosrhoes at Elegia, a town just beyond the Cappadocian frontiers, high up past the headwaters of the Euphrates.

Severianus makes some attempt to fight Chosrhoes, but soon realizes the futility of his campaign, and commits suicide.

His legion is massacred.

The campaign had only lasted three days.

Pius' fortune passes on to Faustina the Younger in accordance with his will. (Marcus has little need of his wife's fortune. Indeed, at his accession, Marcus transfers part of his mother's estate to his nephew, Ummius Quadratus.)

Faustina is three months pregnant at her husband's accession.

During the pregnancy she dreams of giving birth to two serpents, one fiercer than the other.

On August 31, she gives birth at Lanuvium to twins: T. Aurelius Fulvus Antoninus and Lucius Aurelius Commodus.

Aside from the fact that the twins share Caligula's birthday, the omens are favorable, and the astrologers draw positive horoscopes for the children.

The births are celebrated on the imperial coinage.

Marcus' early reign proceeds smoothly.

He is able to give himself wholly to philosophy and the pursuit of popular affection.

Soon, however, Marcus will find he has many anxieties.

It will mean the end of the felicitas temporum ("happy times") that the coinage of 161 so glibly proclaims.

The Parthians, under Vologases IV, have invaded Armenia, deposed its Roman client king in favor of a son of Vologases, and destroyed the Roman legion sent to redress the situation.

There is threat of war on Rome’s other frontiers as well—in Britain, and in Raetia and Upper Germany, where the Chatti of the Taunus mountains have recently crossed over the limes.

Marcus Aurelius is unprepared.

Pius seems to have given him no military experience; the biographer writes that Marcus spent the whole of Pius' twenty-three-year reign at the emperor's side—and not in the provinces, where most previous emperors had spent their early careers.

Marcus makes the necessary appointments: Marcus Statius Priscus, the governor of Britain, is sent to replace the late Severianus as governor of Cappadocia, and is in turn replaced by Sextus Calpurnius Agricola.

More bad news arrives: Attidius Cornelianus' army had been defeated in battle against the Parthians, and retreated in disarray.

Reinforcements are dispatched for the Parthian frontier.

P. Julius Geminius Marcianus, an African senator commanding X Gemina at Vindobona (Vienna), leaves for Cappadocia with vexillations from the Danubian legions.

Three full legions are also sent east: I Minervia from Bonn in Upper Germany, II Adiutrix from Aquincum, and V Macedonica from Troesmis.

The northern frontiers are strategically weakened; frontier governors are told to avoid conflict wherever possible.

Attidius Cornelianus himself is replaced by M. Annius Libo, Marcus' first cousin.

He is young—his first consulship is in 161, so he is probably in his early thirties—and, as a mere patrician, lacks military experience.

Marcus has chosen a reliable man rather than a talented one.

Marcus takes a four-day public holiday at Alsium, a resort town on the Etrurian coast.

He is too anxious to relax.

Writing to his former tutor Marcus Cornelius Fronto, he declares that he will not speak about his holiday.

Fronto encourages Marcus to rest, calling on the example of his predecessors (Pius had enjoyed exercise in the palaestra, fishing, and comedy), going so far as to write up a fable about the gods' division of the day between morning and evening—Marcus had apparently been spending most of his evenings on judicial matters instead of leisure.

Marcus cannot take Fronto's advice.

Fronto sends Marcus a selection of reading material, including Cicero's pro lege Manilia, in which the orator had argued in favor of Pompey taking supreme command in the Mithridatic War.

It is an apt reference (Pompey's war had taken him to Armenia), and may have had some impact on the decision to send Lucius to the eastern front.

To settle his unease over the course of the Parthian war, Fronto writes Marcus a long and considered letter, full of historical references.

In modern editions of Fronto's works, it is labeled De bello Parthico (On the Parthian War).

There had been reverses in Rome's past, Fronto writes, at Allia, at Caudium, at Cannae, at Numantia, Cirta, and Carrhae; under Trajan, Hadrian, and Pius; but, in the end, Romans had always prevailed over their enemies.

The Tiber floods over its banks in the spring of 162, destroying much of Rome, drowning many animals, and leaving the city in famine.

Marcus and Lucius give the crisis their personal attention.

In other times of famine, the emperors are said to have provided for the Italian communities out of the Roman granaries.

Fronto's letters continue through Marcus' early reign.

Fronto feels that, because of Marcus' prominence and public duties, lessons are more important now than they had ever been before.

Fronto again reminds his pupil of the tension between his role and his philosophic pretensions.

The early days of Marcus' reign are the happiest of Fronto's life: his pupil is beloved by the people of Rome, an excellent emperor, a fond pupil, and, perhaps most importantly, as eloquent as could be wished.

Marcus had displayed rhetorical skill in his speech to the senate after an earthquake at Cyzicus.

It had conveyed the drama of the disaster, and the senate had been awed.

Fronto is hugely pleased.

Over the winter of 161–62, as more bad news arrives—a rebellion is brewing in Syria—it is decided that Lucius should direct the Parthian war in person.

He is stronger and healthier than Marcus, the argument goes, more suited to military activity.

Lucius' biographer suggests ulterior motives: to restrain Lucius' debaucheries, to make him thrifty, to reform his morals by the terror of war, to realize that he was an emperor.

Whatever the case, the senate gives its assent, and Lucius leaves.

Marcus will remain in Rome.

Furius Victorinus, one of the two praetorian prefects, is sent with Lucius, as are a pair of senators, M. Pontius Laelianus Larcius Sabinus and M. Iallius Bassus, and part of the Praetorian Guard.

Victorinus had previously served as procurator of Galatia, giving him some experience with eastern affairs.

Moreover, he is far more qualified than his praetorian partner, Cornelius Repentinus, who is said to owe his office to the influence of Pius' mistress Galeria Lysistrate.

Repentius has the rank of a senator, but no real access to senatorial circles—his is merely a decorative title.

Since a prefect has to accompany the Guard, Victorinus is the clear choice.

Laelianus had been governor of both Pannonias and governor of Syria in 153; hence he has firsthand knowledge of the eastern army and military strategy on the frontiers.

He is made comes Augustorum ("companion of the emperors") for his service.

Laelianus is, in the words of Fronto, "a serious man and an old-fashioned disciplinarian".

Bassus had been governor of Lower Moesia, and is also made comes.Lucius selects his favorite freedmen, including Geminus, Agaclytus, Coedes, Eclectus, and Nicomedes, who gives up his duties as praefectus vehiculorum to run the commissariat of the expeditionary force.

The fleet of Misenum is charged with transporting the emperor and general communications and transport.

Lucius leaves in the summer of 162 to take a ship from Brundisium; Marcus follows him as far as Capua.

Lucius feasts himself in the country houses along his route, and hunts at Apulia.

He falls ill at Canosa, probably afflicted with a mild stroke, and takes to bed.

Marcus makes prayers to the gods for his safety in front of the senate, and hurries south to see him.

Fronto is upset at the news, but is reassured when Lucius sends him a letter describing his treatment and recovery.

In his reply, Fronto urges his pupil to moderate his desires, and recommends a few days of quiet bedrest.

Lucius is better after three days' fasting and a bloodletting.

It was probably only a mild stroke.

Co-emperor Lucius Verus continues eastward via Corinth and Athens in the summer of 162, accompanied by musicians and singers as if in a royal progress.

He stays with Herodes Atticus at Athens and joins the Eleusinian Mysteries.

During sacrifice, a falling star is observed in the sky, shooting west to east.

Verus’ journey continues by ship through the Aegean and the southern coasts of Asia Minor, lingering in the famed pleasure resorts of Pamphylia and Cilicia, before arriving in Antioch.

It is not known how long Verus' journey east took; he might not have arrived in Antioch until after 162.

Statius Priscus, meanwhile, must have already arrived in Cappadocia; he will earn fame in 163 for successful generalship.

Lucius spends most of the campaign in Antioch, though he wintered at Laodicea and summers at Daphne, a resort just outside Antioch.

He takes up a mistress named Panthea, from Smyrna.

The biographer calls her a "lowborn girlfriend", but she is probably closer to Lucian's "woman of perfect beauty", more beautiful than any of Phidias and Praxiteles' statues.

Polite, caring, humble, she sings to the lyre perfectly and speaks clear Ionic Greek, spiced with Attic wit.

Panthea reads Lucian's first draft, and criticizes him for flattery.

He had compared her to a goddess, which frightens her—she does not want to become the next Cassiopeia.

She has power, too: she makes Lucius shave his beard for her.

Critics declaim Lucius' luxurious lifestyle.

He has taken to gambling and enjoys the company of actors.

He makes a special request for dispatches from Rome, to keep him updated on how his chariot teams are doing.

He brings a golden statue of the Greens' horse Volucer around with him, as a token of his team spirit.

Fronto defends his pupil against some of these claims: the Roman people need Lucius' bread and circuses to keep them in check.

This, at least, is how the biographer has it.

The whole section of the vita dealing with Lucius' debaucheries (HA Verus 4.4–6.6) is an insertion into a narrative otherwise entirely cribbed from an earlier source.

Some few passages seem genuine; others take and elaborate something from the original.

The rest is by the biographer himself, relying on nothing better than his own imagination.

Lucius faces a heavy task.

Fronto describes the scene in terms recalling Corbulo's arrival one hundred years before.

The Syrian soldiers, having turned soft during the east's long peace, spend more time at the city's open-air bars than in their quarters.

Under Lucius, training is stepped up.

Pontius Laelianus orders that their saddles be stripped of their padding.

Gambling and drinking are sternly policed.

Fronto writes that Lucius was on foot at the head of his army as often as on horseback.

He personally inspects soldiers in the field and at camp, including the sick bay.

Lucius sends Fronto few messages at the beginning of the war, but does send Fronto a letter apologizing for his silence.

He will not detail plans that could change within a day, he writes.

Moreover, there is little thus far to show for his work.

Lucius does not want Fronto to suffer the anxieties that have kept him up day and night.

One reason for Lucius' reticence may have been the collapse of Parthian negotiations after the Roman conquest of Armenia.

Lucius' presentation of terms is seen as cowardice.

The Parthians are not in the mood for peace.

Lucius needs to make extensive imports into Antioch, so he opens a sailing route up the Orontes.

Because the river breaks across a cliff before reaching the city, Lucius orders that a new canal be dug.

After the project is completed, the Orontes' old riverbed dries up, exposing massive bones—the bones of a giant.

Pausanias says they were from a beast "more than eleven cubits" tall; Philostratus says the it was "thirty cubits" tall.

The oracle at Claros declares that they are the bones of the river's spirit.

Verus takes the title Armeniacus, despite having never seen combat, at the end of the year; Marcus declines to accept the title until the following year.

When Lucius is hailed as imperator again, however, Marcus does not hesitate to take the title Imperator II with him.

The army of Syria is reinforced by II Adiutrix and Danubian legions under X Gemina's legate Geminius Marcianus.