the Historia Augusta, the approach of the imperial army to Carnuntum was apparently sufficient to persuade them to withdraw and offer assurances of good conduct. The two emperors returned to Aquileia for the winter, but on the way, in January 169, Lucius Verus died. Marcus returned to Rome to oversee his co-emperor's funeral. Roman expedition against the Iazyges and the Germanic invasion of Italy In the autumn of 169, Marcus set out from Rome, together with his son-in-law Claudius Pompeianus, who would become his closest aide during the war. The Romans had gathered their forces and intended to subdue the independent tribes (especially the Iazyges), who lived between the Danube and the Roman province of Dacia. The Iazyges defeated and killed Marcus Claudius Fronto, Roman governor of Lower Moesia. However, while the Roman army was entangled in this campaign, making little headway, several tribes used the opportunity to cross the frontier and raid Roman territory. To the east, the Costoboci crossed the Danube, ravaged Thrace and descended into the Balkans, reaching Eleusis, near Athens, where they destroyed the temple of the Eleusinian Mysteries. The most important and dangerous invasion, however, was that of the Marcomanni in the west. Their leader, Ballomar, had formed a coalition of Germanic tribes. They crossed the Danube and won a decisive victory over a force of 20,000 Roman soldiers near Carnuntum, in what is sometimes known the Battle of Carnuntum. Ballomar then led the larger part of his host southwards towards Italy, while the remainder ravaged Noricum. The Marcomanni razed Opitergium (Oderzo) and besieged Aquileia. This was the first time that hostile forces had entered Italy since 101 BC, when Gaius Marius defeated the Cimbri. The army of praetorian prefect Titus Furius Victorinus tried to relieve the city, but was defeated and possibly killed during the battle (other sources have him die of the plague). There is no consensus amongst scholars as to the year that the great Germanic invasion towards Aquileia took place. Several authors, like Marcus Aurelius' biographer Frank McLynn, accepting the date of defeat near Carnuntum as 170, place the great Germanic invasion itself three years earlier. They maintain it happened in 167 because by the year 170 the Germans would have been checked by the Praetentura Italiae et Alpium—the fortifications which were erected in 168–169 to block a breakthrough of the Alps to Northern Italy – whereas all sources confirm it