The Roman calendar had reference points for counting the days in the months. The 'ides' would be the middle of the month, and the fifth or the seventh day would be the 'nones', and the 'kalends' were the first day, which is also where the word "calendar" comes from. The actual date of the 'ides' vary because the Ides only falls on the 15th of the month one-third of the time. The actual 'dates' were figured out by counting backwards from the marking points of the ides, nones, and kalends. For example, the March first would be Kalends, March second would be VI Nones, the third of March, V Nones, and so on, counting backwards from the nones, or ides if the date was past the fifth or seventh of the month.