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.