Roman calendar dating
This page allows you to interconvert dates in a variety of calendars, both civil and computer-related.
All calculations are done in Java Script executed in your own browser; complete source code is embedded in or linked to this page, and you're free to download these files to your own computer and use them even when not connected to the Internet.
The Roman calendar organized its months around three days, each of which served as a reference point for counting the other days: The remaining, unnamed days of the month were identified by counting backwards from the Kalends, Nones, or the Ides.
For example, March 3 would be V Nones—5 days before the Nones (the Roman method of counting days was inclusive; in other words, the Nones would be counted as one of the 5 days).
Whether it was Romulus or not, the inventor of this calendar had a penchant for complexity.
Kalends, the word from which calendar is derived, is another exotic-sounding term with a mundane meaning.
Kalendrium means account book in Latin: Kalend, the first of the month, was in Roman times as it is now, the date on which bills are due.
This application deals with only two: the Gregorian calendar, now used universally for civil purposes, and the Julian calendar, its predecessor in the western world.
As used here, the two calendars have identical month names and number of days in each month, and differ only in the rule for leap years.