against the Quadi, who had broken their treaty and assisted their kin, and defeated and subdued them. During this campaign, a famous incident, the so-called "miracle of the rain", occurred, which was later depicted on the column of Marcus Aurelius and on coins. According to Cassius Dio, the legio XII Fulminata was hemmed in by a superior Quadi force and almost forced to surrender because of the heat and thirst. They were saved, however, by a sudden shower, which refreshed the Romans, while lightning struck the Quadi. Contemporaries and historians attributed it to divine intervention: Dio stated that it was called by an Egyptian magician praying to Mercury, while Christian writers such as Tertullian attributed it to a prayer by Christians. In the same year, Didius Iulianus, the commander of the Rhine frontier, repelled another invasion of the Chatti and the Hermunduri, while the Chauci raided the shoreline of Gallia Belgica. In the next year, the Romans marched against the Quadi, whereupon the Quadi deposed their pro-Roman king, Furtius, and installed his rival, Ariogaesus, in his place. Marcus Aurelius refused to recognize him, and turning back, deposed and exiled him to Alexandria. Thus, by late 174, the subjugation of the Quadi was complete. In typical Roman fashion, they were forced to surrender hostages and provide auxiliary contingents for the Roman army, while garrisons were installed throughout their territory. After this, the Romans focused their attention on the Iazyges living in the plain of the river Tisza (expeditio sarmatica). After a few victories, in 175, a treaty was signed. According to its terms, the Iazyges King Zanticus delivered 100,000 Roman prisoners and, in addition, provided 8,000 auxiliary cavalrymen, most of whom (5,500) were sent to Britain. Upon this, Marcus assumed the victory title "Sarmaticus". Marcus Aurelius may have intended to campaign against the remaining tribes, and together with his recent conquests establish two new Roman provinces, Marcomannia and Sarmatia, but whatever his plans, they were cut short by the rebellion of Avidius Cassius in the East. Marcus Aurelius marched eastwards with his army, accompanied by auxiliary detachments of Marcomanni, Quadi and Naristi under the command of Marcus Valerius Maximianus. After the successful suppression of Cassius' revolt, the emperor returned to Rome for the first time in nearly 8 years. On 23 December 176, together with his son Commodus, he celebrated a joint triumph for his German victories ("de Germanis" and "de