Themiclesian calendar

The Themiclesian calendars are a lunisolar calendar employed in Themclesia for certain legal, administrative, and social purposes, and a solar calendar for ritualistic purposes. Though largely supplanted by the Casaterran calendar in the 19th century for commerce, the Themiclesian calendar is still used for cultural events, fortune-telling, and numerous others. It enjoys co-official status with the Gregorian calendar though limited actual use.

Lunisolar calendar

Lunar month

The lunar month is based on the phases of the moon. Rather than following a single cycle that encompasses the whole gamut of the moon's phases, there are two simultaneous cycles that point to various parts of the month. In annual usage, a lunar month alternating lengths of 29 and 30 days.

The first cycle, and probably the more ancient, recognizes two points in the moon's phases, the new crescent moon (朏, pei’ or pjei’) and the first day past full moon (既望, kjeis-mjangs). The crescent moon has been defined as the third day of a month when the previous month was 29 days, or the second day when the prevoius had 30. The full moon is always 15 days exactly from the crescent. It has been noted as an anomaly that the crescent moon is not adopted as the first day of each month, rather the first moonless day. Scholars studying bronze inscriptions unearthed in Menghe have suggested that, prior to the 9th century BCE, it was indeed the crescent moon that heralded the commencement of the new month. The shift of the beginning of the month probably indicates the detachment of the calendar from actual astronomical observations, which in turn indicates the development of a mathematical understanding of the movement of the celestial bodies that function as timepieces.

The second cycle recognizes four other points in a lunation. The first is the moonless night (朔, sngrak) following the waning crescent of the previous lunation. The day following (既死霸, kjedh-sji'-pragh), if the previous month was 29 days, is given special standing. Bronze inscriptions further indicate this term should be synonymous with the moonless night, but in Themiclesia its meaning has shifted to the day following. The eighth day of each lunation is termed the waxing crescent (既生霸, kjedh-srêng-pragh), regardless of the length of the previous month, and the twenty-third day is the waning crescent (方死霸, pjang-srêng-pragh). The day on which the moon is last seen before disappearing is hmegh (晦).

Hemeral day
Short month	Menghean date		27	28	29	30	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	1	2	3	4	5
	Minor cycle	Marker						A															B															A
		Month	Last month					This month																														Next month
	Major cycle	Marker					A	B						C							D														E	A
		Month	Last month				This month																													Next month
Long month	Menghean date		27	28	29	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	1	2	3	4	5
	Minor cycle	Marker						A															B														A
		Month	Last month					This month																													Next month
	Major cycle	Marker				A		B					C								D														E	A
		Month	Last month			This month																														Next month

Lunisolar year

The lunisolar year is divided into twelve lunar months that correspond to actual lunations, which have alternating lengths of 29 and 30 days. A normal lunisolar year thus has 354 days. Such a system would, if left alone, quickly become desynchronized from the seasonal cycle, which would be detrimental to agriculture. Early Themiclesians practiced collective farming, where the entire community would perform the same thing on their respective lands, ostensibly for mutual assistance and economies of scale. This relied on a calendar that predicted changes in weather accurately, and in later ages it was a culturally symbolic role for the state to issue the following year's calendar. It was thus necessary to add intercalary months to retard the progression of the lunisolar year. During the Gojun dynasty in Menghe, rulers arbitrarily added intercalary months but sometimes followed rules such as one every third year, or two in the space of five. Eventually, in Menghe as in Themiclesia, the Metonic cycle was adopted shortly before the common era, with seven intercalary months added to 19 lunar years.

The process for determining the placement of these months varied according by state and sometimes fluctuated within them during the Hexarchy. The most widespread practice seems to be adding the month to the end of the 12-month year. Under traditional nomenclature, where months are named cardinally, the intercalary month was the "Thirteenth Month" (十三月). This remains the practice of the administrative calendar, which preserves some archaicisms as it was not necessary to correct anomalies as accurately as for agricultural purposes. However, as astronomical observation improved, the intercalary month was placed in relation to the solar year. In such a way, as soon as the lunar calendar progressed more than 1/24 along its annual cycle than the Septentrion did the ecliptic, an additional month was added. The ecliptic was divided into 24 segments, each 15° apart, with the 0° mark arbitrarily fixed on the perihelion, or winter solstice on Septentrion. This meat that the lunar year was now 1/24 behind the progression of the solar year, so the net deviation was equally distributed. During non-leap years, the administrative and agricultural calendars are exactly the same, but the former is one month faster than the latter after the official intercalary month is placed on the latter.

The relationship between the agricultural and administrative calendars are illustrated as follows.

Lunations
Minor	Year	Year N-1					Year N													Year N+1
	Month	8th	9th	10th	11th	12th	1st	2nd	3rd	4th	5th	6th	7th	7th	8th	9th	10th	11th	12th	1st	2nd
Major	Year	Year N-1		Year N												Year N+1
	Month	8th	9th	10th	11th	12th	1st	2nd	3rd	4th	5th	6th	7th	8th	9th	10th	11th	12th	13th	1st	2nd

Solar calendar

The solar calendar was a liturgical calendar in Themiclesia seeing extremely limited daily use. Despite being named the "solar" calendar (太陽曆, t'adh-lang-rêk), it is in fact based on a hexagenary hemeral cycle that repeats without regard for the progression of the sun. This cycle may be connected with the mythical idea that there were ten suns in the sky, sequentially appearing for one day each, then looping indefinitely, though scholars have argued that the myth is probably an apocryphal creation to explain the use of a ten-day hemeral cycle. Each of the ten days were named, and the cycle was called the sgwjel (旬), sometimes also called the Menghean week. Additionally, each day was then connected with a twelve-member sequence, forming sixty unique combinations.

See also

• Themiclesia