Roman Day is a term used to refer to the three days of the Roman calendar that were considered important. Nones, Ides, and Dies are the three days that make up Roman Day. Nones is the fifth day of the month, Ides is the thirteenth day of the month, and Dies is the fifteenth day of the month. These three days were considered important because they marked the beginning and end of the month, as well as the midpoint of the month.