The Romans campaign against the Quadi, who had broken their treaty and assisted their kin, in 173 .
During this campaign, the so-called "miracle of the rain" occurs, a famous incident that will later be 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 attribute it to divine intervention: Dio will claim that it was called by an Egyptian magician praying to Mercury, while Christian writers such as Tertullian attributed it to a prayer by Christians.
The Romans defeat and subdue the Quadi.
