According to one Roman myth, Mamurius was a smith who was run out of the city because the shields he had made for the Roman soldiers failed to protect them when they were substituted for the sacred shield that had fallen from heaven. Another explanation for the ceremonies held on this day is that Mamurius, whose name was a variation of Mars, represented the old year, which had to be driven away on the day preceding the first full moon of the new Roman year. In any case, the rite that took place on March 14 involved leading a man wearing only animal skins through the streets of Rome. He was pursued and beaten with long white rods until he was driven out of the city.
The Mamuralia was unusual in that no other Roman festival occurred on an even-numbered day. One explanation is that the festival was originally held on the Ides of March, but was moved back a day so that people could attend both the horseraces known as the Equirria and the Anna Parenna Festival held on March 15.