Robigalia was an old Roman festival in honor of the deities Robigo and Robigus, celebrated on April 25. Traditionally established by Numa Pompilius. According to the Romans, Robigo was a deity responsible for securing crops against the so-called grain rust that destroyed huge amounts of fields.
During Robigalia, the retinue of the faithful went to the sacred grove, where Flamen Quirinalis sacrificed a red dog and sheep to protect the crops from crop failure. Then races (ludi cursoribus) were organized in honor of Mars and Robigo. There were two kinds of races: the younger participants drove two-horse chariots (biga), and the more experienced ones sat in the four-horse (quadriga).