Drithidian calendar
The Drithidian calendar is the calendar now in common usage throughout most of the developed nations of Dadauar, as well as many of the undeveloped nations. The abbreviation "D.C." is sometimes used after a Drithidian date, but is usually redundant; a date on Dadauar is usually given according to the Drithidian calendar unless otherwise specified. Unlike the Julian calendar on Earth, the Drithidian calendar does have a year zero; before year zero dates are written as negative numbers. For the most part, Dadauar is described in the Wongery as it is in the year 2789 D.C.
Year Zero
Year zero of the Drithidian calendar is often said to date from the founding of the first modern onirarchy. Technically, however, this isn't strictly accurate. The first modern onirarchy is generally held to have been the now-vanished nation of Radess, which was founded, by the Drithidian calendar, in the year -63. What the Drithidian calendar is actually based on is the foundation of the nation of Drithidiach, which, by most reckonings, was actually the third modern onirarchy, after Radess and Ki Lun. Drithidiach was, however, the first onirarchy to spread to a large empire—though most of that empire has since been lost—, and it was in Drithidiach, naturally, that the Drithidian calendar was formulated.
More specifically, year zero of the Drithidian calendar marks the occasion when Issen Tocht, the first onirarchal leader of Drithidiach, was officially declared the nation's leader. This happened on the fifth day of the fourth month of the year, a day still celebrated in Drithidiach and certain other nations as the Day of Foundation.
Days of the Year
The Drithidian calendar year lasts exactly 334 days. This was originally based on the time it took for one temperature cycle to complete, the year beginning when the temperatures were most uniform—that is, coldest in the tropical regions and warmest in the arctic. As the number of days in one cycle is not an integer, however, over time the calendar year becomes increasingly out of sync with the temperature cycle. Since the actual number of days in a temperature cycle is, to two decimal places, 334.28, the offset grows by about two days every seven years.
Though this discrepancy could be ameliorated by a system of leap days, so far no such system has been put into widespread use. For sixteen hundred years, the difference in the cycles was simply tolerated, the difference between the calendar year and the climatic year accepted as a fact of life. Finally, however, in 1623, Polger Nathon, president of the Free Republic of Avelax, proposed that the calendar year be brought back into alignment with the temperature cycle. At that time, Avelax was the most powerful nation on Dadauar, and the other onirarchies quickly fell into line; the next time the temperature cycle hit its peak uniformity, the new year was declared. This occurred less than halfway into 1624, though, rendering that year only 120 days long—this so-called "Rump Year" still causes occasional headaches for historians.
Since then, the climatic year and the Drithidian calendar year have never been allowed to get too far out of sync with each other. Instead of a more gradual and systematic solution, however, a whole extra leap month has been added at irregular intervals. So far, no more regular system has been agreed on, and the extra month has simply been added whenever the onirarchies jointly decide that the difference between the cycles is becoming too great, which has generally been about once a century. The last intercalary month was added twenty-six years ago, in 2769, so currently the discrepancy only amounts to about nine days, and another intercalary month is unlikely to occur soon.
Months of the Year
The Drithidian calendar borrows from a number of older calendars in an attempt to be inclusive of all the cultures that composed the Drithidian Empire at the time of the calendar's design. This makes it rather a haphazard hash, its thirteen months varying widely in length from eight days to thirty-five. Days are numbered from the end of the month, and referred to using cardinal numbers; the last day of a month is therefore called the One of the month, the second-to-last day the Two, and so forth.