The Carycian calendar has been adopted by many countries since its invention by the Blue Monk, Frezzi Alberto, in the year 1. It evolved from the wonderment Alberto felt for the natural cycles and his attempts to understand and predict them.
The Six Cycles
Its basic unit of time is the cycle of Veneris, the smaller of the two moons, whose period is approximately fourty-eight days in length. The most obvious pattern, observed long before Alberto, was that the period of Alteris was exactly half that of Veneris. Thus the calendar uses the eight-stages of relative phase (e.g. full-full, gibbous-crescent, etc.) to break up the fourty-eight day “months” into six day “weeks” (see attached diagram).
Six cycles of Veneris correspond to one year. The actual natural yearis a little shorter than this, and this is compensated for by a five-cycle year every century.
Note: Since the Carycian number system uses base 12 (see attached diagram) a century in this calendar corresponds to a period of 144 years.
The six cycles of Veneris are named:
caliscalo - midwinter (calis = ice)
priscalo - spring (prisco = foliage)
boccalo - early summer (bocco = storm)
siecalo - high summer (siecis = heat)
armescalo - harvest (armis = harvest)
freddescalo - winter (freddo = cold)
The Method of Alberto
The method Alberto used to calculate equinoxes and solstices is essentially geometrical. He would draw a hexagon with the six cycles as vertices, then inscribe another polygon inside the hexagon. This polygon was almost a hexagon, but had to wind around inside the fundamental hexagon 144 times before it met its end again. This corresponds to the non-equality of the period of a year to the six-cycle period of Veneris, hence the five-cycle correction. At certain points of intersection of the two polygons and the intersections of lines bisecting the side of the internal polygon with the outer hexagon Alberto showed that there must occur ecliptic extrema (e.g. solstices).
The Naming of the Years
In recent years, largely for the benefit of the illiterate populace, the years are given names as well as numbers. They are usually named after events that took place during that year, or simply to give an impression of the current Zeitgeist.
The naming ceremony takes place in the Piazza dei Clonchi, presided over by the Duke. He will read out the possible names to a crowd of hundreds, and they will cheer for their preferred name. The name which receives the most rapturous reception is then used. To have your name attached to a year (e.g. The Year of the Triumph of Fred Mills) would be a great honour, and very much sought by the adventuring community.
The Numbering System
While most of the merchant cities now work in base five or ten (due to the ease of calculation afforded by five-fingered hands) the years are still counted in base twelve, because twelve is such an important number in the cycles of Alberto. The concept of “zero” is still alien to mathematics, and to compensate for this a devious trick is used. Say the digits were A,B,C,D,E,F,G,H,I,J,K. Then instead of writing A0 for 12, you would write L, then move over into AA, AB, etc. for 13, 14 etc. Similarly, 23,24,25 would be written AK,AL,BA.
The actual digits used are constructed from an earlier (base four) system, and can be seen in the attached file.