The Rain Miracle: the miraculous escape of the Twelfth Legion Fulminata during the Marcomannic Wars.
In the winter of 168/169, the Roman emperor Marcus Aurelius launched a large-scale war against the tribes across the northern frontier of the empire: the Marcomanni and Quadi in Czechia. After initial setbacks, they were defeated in 174. During this campaign, the legion called XII Fulminata (the 'Thundering legion') was surrounded by the Quadi and almost forced into surrender because it had no water. However, when disaster seemed inevitable, a heavy shower relieved the Romans. This seems to have happened in 172.
Immediately, there were several traditions about the cause of the miracle. According to Cassius Dio, a Greek historian who wrote some 40 years after the event, an Egyptian magician had been able to work the miracle (Roman History, 72=71.8-10). On the other hand, his contemporary Tertullian, a Christian author, claimed that the prayer of Christian soldiers had caused the miracle. Other sources on the incident are coins and a relief on the honorary column of Marcus Aurelius.
The Roman History of Cassius Dio is partly lost, but an excerpt by the Byzantine author Xiphilinus survives. It is quoted below, including an addition by Xiphilinus, who accuses Dio of fraud.
The translation was made by E. Cary.