Most fall festivals focus on feasting, but Romans observed a day of fasting on October 4 called iēiūnium Cerēris. In 191 BC, the Senate ordered the decimvirī to consult the Sibylline books, which prescribed that a fast in honor of Ceres should be held every five years. In Augustus's day, the iēiūnium Cerēris was held every year on October 4.