The Religious Calendar of the Ruzi
It's estimated that the calendar drifted 1 day in every 3 years.
The Standard Calendar of the Aznowa Confederation
The Standard Calendar of the Aznowa Confederation was a Solar Calendar that had 12 months of different lengths. Every 3rd year an intercalary day was added to the last month of the year. This calendar used a week of 7 days.
The days of the months were as following
- 27 days: 2nd, 4th, 5th, 8th, 10th, and 11th month
- 28 days: 6th and 12th month, except in leap years
- 29 days: 1st, 3rd, 7th, 9th, and 12th month in a leap year.
The calendar had a total of 334 days, with 335 in leap years.
It's estimated that the calendar drifted 1 day in 85 years.
The Qakhomatzian Calendar
The Qakhomatzian calendar was a semi-lunar calendar of 11 months of 29 days, except for the first and last month of the year. To keep the calendar in sync with the stars, an intercalary month would be added by royal decree. Most years therefore had 317 days, with the odd leap year enjoying 356 days. Like the Aznowa calendar, each week had 7 days.
The Zjonyo Calendar
The days of the months were as following:
- 30 days: 2nd, 4th, 5th, 6th (except in a leap year), 7th, 8th, and 10th
- 31 days: 1st, 3rd, 6th (in a leap year), 9th, 11th
After having been in use for almost 360 years, it was obvious that this calendar drifted compared to the stars. To deal with this drift, 622 a.Q. had 1 day added to each month, with 1 additional day added to the 4th month, making it also 32 days long, which made 622 a.Q a 346 days long year. The year after, the current calendar was introduced.
The Illome Calendar
The current calendar, the Illome calendar, is a cyclic lunisolar calendar. Since its introduction in 623 a.Q, the calendar is calculated to only having drifted ahead of the stars by less than half a day in 490 years.
The design of the calendar was that a calendar round, саłь (zarq) /zaɹq/, would have 26 year, where 11 years in a round would have 11 months and a year length of 317 days, with the remaining 15 years having 12 months and a year length of 346 days, with an intercalary day added to the last year in the round, unless it also was the last year of a long count, левісаłь (levizarq) /le:vizaɹq/, of 36 calendar rounds. This way would ensure that the stellar drift of the calendar would be negligible even after a completed long count of 936 years.
It was also suggested by the committee that the years should be counted from the Day of Qakhomatze, 623 a.Q. Thus new years day, Flauw 1st 623 a.Q would be written as 126.96.36.199.1, or 1.1.1.Flauw.1. Hope 12th, 1113 a.Q would then have been known as 188.8.131.52.12. This new era system was never officially implemented, but are still well documented and known to interested parties.
The days of the months are as follow:
- 28 days: 1st and 11th month (except in leap years, and if it's the last month of a calendar round, except if it's the last month of the long count).
- 29 days: all other months.
The years of the calendar round are as follow:
- 317 days (11 months): 1st, 3rd, 5th, 8th, 10th, 13th, 15th, 18th, 21st, 24th (and 26th, if it's the year of the last calendar round of a long count).
- 318 days (11 months): 26th year (unless the last year in a long count).
- 347 days (12 months): all other years.
The Illome Calendar is estimated to drift a single day in about 600 long count cycles, or more than half a million years.