Ancient Romans originally used the lunar calendar, which specified the day of the new moon and that of the full moon. Even after switching to the solar calendar, they continued to use the same way of naming dates. The first day of the month was called "kalendae" even if it was not the day of the new moon, and the middle of the month was called "idus" even if it was not the day of the full moon. The day of the first quarter moon was called "nonae". Other days were expressed as a certain number of days prior to the kalendae, nonae or idus, counting inclusively, that is, including the kalendae, etc. The table below shows how the days of March were named.