The Calendar

Running Reality uses the Gregorian Calendar, exclusively. All dates for data must be in the Gregorian Calendar and all dates displayed are in the Gregorian Calendar.

The Gregorian Calendar

The Gregorian Calendar is the calendar for most western nations and English speaking nations. Nearly all modern English-language written history uses Gregorian calendar dates. The calendar is a solar calendar with a solar year, lunar months, and a fixed-length day tied to the Earth's rotation. The calendar was instituted in 1582 at the direction of Pope Gregory XIII and superceded the Julian calendar that had been in effect throughout most of the lands of the Roman Empire since being introduced in 46BC by Julius Caesar.

The calendar was intended to fix the slight difference between the Earth's orbit of 365.2425 days and the Julian calendar's year length of 365.25 days. The equinoxes had drifted by 10 days from their calendar date. The fix involved a one-time adjustment that skipped 10 full days in October of 1582, plus an adjustment to the leap-year rule to prevent additional slippage. Under the Julian calendar, every four years was a leap year, but under the Gregorian calendar, only one in every four century years is a leap year.

The calendar was not immediately adopted, but over time it has become the most widely used calendar in the world. Catholic nations adopted the calendar quickly in 1582, while Protestant and Orthodox Christian nations and nations with non-Christian religions adopted it later. In particular, England and it's possessions and colonies did not adopt the Gregorian Calendar until 1752, nearly 170 years later. This means that primary source documents, especially those in the English language, may have had Julian dates for many years after 1582.

Another associated question is the date for New Year's Day. In modern times this date is January 1, but it has also been March 1 in many nations across many years. Depending on the calendar in effect at the time, primary source documents written where New Year's Day was March 1 may have different years for dates falling during January and February.

Finally, dates in history were not chronological to a universal origin. They were usually "in the 5th year of the reign of..." relative-style dates. The current year numbering system used in the Gregorian Calendar and therefore by Running Reality was first developed in 525AD in Europe.

The Rationale

Running Reality has chosen to use the Gregorian Calendar, which will make sense to most people, but also chosen to use it exclusively. The decision to use it exclusively is driven by the difficulty of generating tooling for multiple calendars. We have not precluded the ability to do this; however, so we could revisit it at a later date. Still, for the foreseeable future all factoid input data much be Gregorian and all user interface displays will be Gregorian.

Another aspect of the calendar decision is the requirement that all data fed into the Running Reality engine must have an exact date. This is not consistent with the approach taken for factoids where they should never be required to have more fidelity than can be verified as historical truth. There are many dates in history that are fuzzy (born in 1721 or 1722...), very fuzzy (founded in the 12th century...), or relative (in the 5th year of the reign...). The convention in Running Reality is to have factoids for such dates rounded off to the beginning of the range so that objects will appear in the map for the entire range period. This leads to a large number of factoids on January 1 of a given year. This should be made consistent so that the factoids only contain the year, decade, or century. The necessary adjustments would then be made in the engine by inference and not be hard-coded into the factoid as if it were fact.

Potential for Alternate Calendars

Allowing alternate calendars in Running Reality would open up some interesting possibilities. While the core world engine will always continue to use the Gregorian Calendar, the data inputs to the engine (primarily factoids) and the outputs to the user interface could be values in other formats.

For dates which weren't numerical, it will probably never be worth it to build the complex software code for either input or output in those formats. However, we will keep the option open to be able to give dates in terms of "year of reign" for a monarch or "year of office" for a consulship.