The rex sacrorum would appear on the steps of the Capitol on this day and announce to the people what days of the months would be holidays. The Nones mark the ninth day before the Ides.
It was on this day that the water of a spring by the temple of Dionysos on the Greek island of Andros was supposed to taste like wine. It continued to do so for one week. If the water was taken out of sight of the temple, then it would loose its taste. (Blackburn)
In Greece, this day was the Festival of Kore.
This day marked the birthday of the shrine of Vica Pota at Rome.