Early Aurian Calendar (pre-imperial era):
Asūr'el
Azus
Sòlus
Sīgilus
Alassel
Yrellus
Saulel
Ūrusel
Metosel
Sì'el
The early calendar tracked ten months divided into 30 days each with accumulated drift over time. It was created by King Providence when he first arrived in the Sunlight Plains and purposefully excluded Winter (The Great Cold Omen), which was a period bereft of agricultural activity. It tracked the lunar cycles of the Black Moon (25.32 day lunar phase) and the Lunar Mutual period as its calendar year (301 days). As the Black Moon's lunar phase did not perfectly add up to a lunar year, and its phase periods were only roughly 25 days long, 51 days were distributed across the months evenly to align the difference between calendar months and Lunar Mutual periods. The first month, Asūr'el, named after the Greater God of Conflict and Change was given an extra day, making it 31 days long. The imbalance of days was considered aligned with the principles of Asūr's domain and thus was a positive omen.
As the agricultural calendar and the lunar calendar would eventually grow out of sync, King Calishus would implement the Calishus Method to realign the agricultural year with the lunar year by syncing the calendar year systems between the agricultural and the lunar calendar. Officially, 6 lunar years equals 5 solar years, based on the White Moon Lunar Mutual Eclipse phenomenon with full planetary shade. This becomes known as the Calishite Cycle.
In the countryside, the Equinox Calendar persists. Solar seasons paired with specific Lunar dates allow countryside farmers of the Sunlight Plains to upkeep annual harvests without missing important yearly events or imperial decrees.
Post-Sargonos Calendar:
Months:
Providence
Caladrë
Sòlus
Rèus
Raatateth
Urielos
Kleos
Ex'caladrë
Sīgrèrel
Aeolus
Sì'el
During the reign of the Puppet King Sargonos, the persecution of the priestly class greatly misaligned the calendars and lack of proper documentation caused astrologers to lose the Calishite Cycle. After the deposition of Sargonos, the calendar system was restored, tracking the Black Moon's phases (25.32 days), the Lunar Year, and the Calishite Cycle once more. However, another month was added to organize the calendar. The last month–the month of Sì'el–was considered inauspicious for its association with darkness and secrets (Sìa being the Greater Goddess of Secrets). To offset the bad omen, astrologists allotted 30 days to the month, the number 30 being a multiplicity of 3 (positive omen) and an even number (associated with balance, order, and peacefulness). The remaining 20 days were evenly dispersed among the other months, with the exception of the month of Aeolus which became 28 days, therefore making each remaining month 27 days long for a full 301 day lunar year including the Calishite Cycle.
This adjusted calendar changed the traditional months (originally named after the ten Greater Gods) to fit the astrological phenomena observed in the night sky. King Kleophoros changed the first month to be Providence, named after the first king of Aurumere. The astrologers noted the patterns of the Comets of Caladrë orbiting the White Moon and named the second month after the period when the comets are visible in the night sky. As faith in the Greater God Sòl had peaked during this period and He was largely considered responsible for the legitimacy of the current king during the time, Sòlus remained unchanged in the calendar. The fourth month was renamed to Rèus (literally meaning "fourth)" in order to avoid confusion between Sīgilus (former fourth month in the old calendar), and Sīgrèrel (spelled with the same base character). The fifth month was called Raatateth after the "Angry Eye" lunar mutual. Occasionally (every 3 lunar cycles) a partial mutual would occur between the White Moon and Black Moon where the Black Moon would pass over the White Moon on the upper or lower side of it, appearing like an "Angry Eye" gazing up or down. Thus it was named Raatateth after this occasional phenomenon. To honor the sixth and seventh kings of Aurumere (regent Urielos and later King Kleophoros), the priests named the sixth and seventh months after them. The eighth month was named Ex'Caladrë since this is the period of the year when the comets are no longer visible around the White Moon. The ninth month was named Sīgrèrel after the Quadrature period of the White Moon and the tenth month was called Aeolus, literally meaning "tenth." It was the additional month which court astrologers placed after Sīgrèrel (formerly known as Metosel) and before Sì'el.
This adjusted calendar was modeled after the original calendar but essentially built from the ground up to restore the lost lunar cycle that had been disrupted by the tyranny of Sargonos and his Effinitian wife, Amesra. It had eleven months and maintained a 301 lunar year with a drift/sync Calishite Cycle that stabilized every six lunar cycles. This calendar system also marked the empire's strong shift towards solar worship and veneration of the sun god Sòl.
The Raathorian Calendar:
Providence
Caladrë
Sòlus
Rèus
Raatateth
Urielos
Kleos
Ex'caladrë
Sīgrèrel
Aeolus
Sì'el
Raathel
The Raathorian Calendar was an adjustment made by the promising and tragic King Raath, last of the Aurian kings. He kept most of the calendar's important events and signifiers in place, but merged the agricultural calendar and the lunar calendar together into one solar calendar. This was as much a political move on Raath's part, as it was a function of his office. Having conquered much of the known world by that point, Aurian internal politics had become far more complex than external wars by now. Interior detractors argued that Raath's ambitions risked angering the Gods. He created the solar calendar to appease the faithful, primarily those of the church of Sòl. The solar calendar had a 361.2 day year with a leap year every five cycles.
This was not only a move to appease the faithful though. Many of Raath's detractors appealed to the amorality of slavery and the cruel treatment of the dwarves under Aurian rule. Since slavery was an ancient practice of the empire, and dwarven slaves were among the most common in the empire, they were disproportionately treated cruelly by their Aurian masters. Raath's detractors sought to reign in the king's authority by using this moral argument as leverage to sway the public in their favor. Raath, not wanting to lose popular appeal (which had largely been the base of his political power), agreed to enact a slavery clause into law that would ban certain behaviors and treatment towards slaves by their masters. However, in order to delay this promise, he said that the law would be enacted only at the beginning of the next year.
This is where the solar system became important. In order to make the necessary change from the lunar 301 day year, to the solar 361 day year, an additional 61 days had to be added to the calendar. Additionally, they were in the midst of a seasonal drift, and so another 84 days had to be added after the court astrologers calculated how many days off from the solar year they were. The grand total of extra days which had to be added was 145 days. Of this total, 41 days were distributed evenly to every month except Sì'el, putting them each at 31 days with one extra day being added to Sì'el. After this was done, the remaining 104 days were added to a new twelfth month initially called Ae'terel (literally meaning "twelfth)" but was later during the rise of the Helios kingdom renamed to Raathel, the Month of Raath. The year that the Raathorian Calendar was implemented, its first year was recorded as 446 days long. Subsequent years were standard at 361 days, with the last month being 19 days long or 20 days on leap years.
This allowed King Raath to significantly stall the legal implementation of the new slave codes. Meanwhile, other legal bills and documentation were introduced under the guise of making slavery a "more thorough" process. But in reality, it was used to create so much paperwork and processing that nothing could be done. This made it so that when the new slave codes finally came out on the new year, they were trivialized by other existing bureaucratic structures. King Raath's calendar system was also significantly more accurate than the original system. Its competence as a system made it difficult for detractors to fight against in the royal court. The Raathorian Calendar was the last major adjustment to the western calendar system as of 3rd age; year 1156. The Kings of Helios would later implement a dynasty calendar based on the Aurian kings to track their own holidays, but this was separate from the Raathorian Calendar, which continued to be used in courts, religion, and agriculture.