Dating System

Clan of the Cats uses the usual western Gregorian calendar (also called the New style calendar) introduced in AD 1582 by Pope Gregory XIII to reset the calendar to match the seasons and better keep both in synchronisation. The Julian year then in use was 365 days, 6 hours. The actual value for the Solar year is 365 days, 5 hours, 48 minutes, 46 seconds. The discrepency caused the seasons to regress by almost one day per century.

Gregory chose to reset the vernal equinox (then falling on the eleventh of March) to the twenty-first of March, its date in AD 325 at the Council of Nicea. The change was accomplished very simply by having the day AD 1582-10-04 followed by AD 1582-10-15. Additionally, the leap-year rule was changed from every four years to a somewhat more complicated formula:
  A year is a leap year if it is evenly divisible by four unless
    it is evenly divisible by 100 unless
      it is evenly divisible by 400 unless
        it is evenly divisible by 4000.
This accounting keeps the calendar accurate to within one day in 20 000 years.

These Gregorian reforms were adopted immediately by Catholic countries: the Italies, Portugal, Spain, and the Catholic Germanies. The Protestant Germanies changed over in 1699. England and her colonies switched in 1752, Sweden in 1753, Japan in 1873, China in 1912, Soviet Union in 1918, and Greece in 1923. Other jurisdictions use other calendar systems.

For the Clan of the Cats Mythos Reference, we use the abbreviations CE and BCE instead of AD and BC, to avoid any possible religious toe-stepping. Otherwise, the dating system should be familiar to most English-speaking readers, as well as anyone familiar with European tradition. Additionally, we use the international date format: yyyy-mm-dd.

For people who can’t bear not knowing what an abbreviation means, here is the list:

• CE - usually “Common Era”, though occasionally “Christian Era” is used
• BCE - “Before Common Era”
• AD - “Anno Domini” (Latin: “Year of Our Lord”)
• BC - “Before Christ”

There is one thing you have to remember about the CE-BCE dating system: there is no year zero. Zero was a later Arabic invention, the benefit of which we received when we started using the Arabic numeration instead of Roman. This is also called positional notation, for anyone interested in further trivia. (Try multiplication with Roman numerals sometime, without cheating and converting to Arabic. You’ll see what I mean.) Therefore, for dates, you count ...2 BCE, 1 BCE, 1 CE, 2 CE.... Therefore, although regular numbers (integers) say that -1 to +1 is a span of two units, 1 BCE to 1 CE is only one unit. This can result in spans being “one year out”, much to the annoyance of Researchers and others. This is also the reason why initial years for CE decades, centuries, and millenia always end with a digit “1” not a digit “0”. (Yes, I’m in the 2001-started-the-millenium camp.)

(One benefit to using Atomic Era dating would be that there is a Year Zero. On 1942-12-02 CE, Enrico Fermi’s atomic pile began a self-sustaining chain reaction at the University of Chicago. So 2000 CE = 58 AE. And 100 AE is the first year of the Second Century Atomic Era.)

References

• “AD”. The Canadian Oxford Dictionary. Katherine Barver, ed. Oxford University Press. Toronto: 1998
• “AUC”. Ibid.
• “BC”. Ibid.
• “BCE”. Ibid.
• “CE”. Ibid.
• “Fermi, Enrico”. The New Encyclopaedia Britannica. v.4. 15th ed. Encyclopaedia Britannica, Inc. Chicago: 1998.
• “Gregorian calendar”. The Canadian Oxford Dictionary. Op.cit.
• “Gregorian calendar”. The New Encyclopaedia Britannica. v.5. Op.cit.

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