The calendar used across most of Aletheia is solar in structure, lunar in symbolism, and practical in daily life. It predates the Cataclysm and was widely re-established afterward with little alteration. While local variations exist, the underlying system remains remarkably consistent across regions.
This article explains how the calendar works, what is fixed, what moves, and how the Mid-Summer Festival fits into the year.
The Day
A day in Aletheia is 25 hours long.
This is not considered unusual by its inhabitants; it is simply the natural rhythm of the world. The slightly longer day results in:
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marginally longer work periods
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marginally longer rest periods
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a subtly different daily cadence compared to Earth
The difference is small enough that seasonal rhythms still feel familiar to players and readers, but large enough to distinguish the setting from Earth.
The Year
True Solar Year
The true solar year lasts approximately 372.2 days.
This fractional value is important. Without correction, the calendar would drift relative to the seasons.
Civic Year
The civic year consists of:
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372 days in a normal year
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373 days every fifth year
The additional day every fifth year prevents long-term seasonal drift.
This correction is simple by design and has been part of the calendar for centuries.
Leap Year Rule
Because the solar year exceeds 372 days by roughly 0.2 days, the calendar adds:
One Leap Day every five years
0.2 × 5 = 1 day
This keeps the calendar aligned with the seasons without requiring complex century rules or astronomical reform.
Placement of Leap Day
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The Leap Day occurs during the Mid-Summer Festival.
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It is inserted after the third day of the festival.
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It is not part of any month.
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It is not part of the weekly cycle.
The weekday sequence pauses for Leap Day and resumes normally afterward.
Because it occurs during the largest celebration of the year, Leap Day is widely treated as an especially auspicious festival day.
Months
The year is divided into 12 months of 31 days each.
31 × 12 = 372 days
Month numbering is stable and does not change in leap years.
Across most of the world the months are known by their High Speech names, derived from an ancient liturgical language related to Latin. These names were standardized long before the Cataclysm and remain the formal calendar used in records, contracts, and temple observances.
The High Speech month names are:
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Brumalis — deep winter, from bruma (the solstice and shortest days)
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Gelidus — the cold or frost season
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Vernalis — the turning toward spring
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Amoris — the month of love and courtship
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Florentis — the flourishing or blooming season
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Solis — the height of the sun and longest days
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Aestivus — the heat of summer
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Fructoris — the season of ripening fruit and yield
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Aurelis — the golden season of late harvest
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Ventorum — the winds and shifting weather
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Umbrae — the lengthening shadows
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Silentium — the quiet before midwinter
These names are widely recognized across cultures even where other languages dominate everyday speech.
Many regions also use vernacular equivalents in conversation. Portuguese, French, English, German, and northern languages such as Icelandic or Swedish often translate or adapt the names locally. These variations tend to remain close in meaning to the High Speech originals.
One well-known cultural example is Amoris, associated in some regions with a dramatic spring fruit commonly called Chamas do Amor (“Flames of Love”). The fruit name likely developed from the month’s traditional association with romance and courtship rather than the other way around.
The Week
Aletheia uses a six-day week.
There are exactly:
62 weeks in a standard year
This division is mathematically clean and historically practical.
Days of the Week (High Speech)
The formal names derive from High Speech numerical forms:
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Primus — first day
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Secundus — second day
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Tertius — third day
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Quartus — fourth day
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Quintus — fifth day
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Deorum — the day of the gods
In formal writing these originally appeared as Dies Primus, Dies Secundus, and so forth, but the word Dies (“day”) is usually omitted in everyday speech.
The sixth day, Deorum (“of the gods”), is traditionally associated with reduced labor, temple visits, civic gatherings, and rest. It is not a universal mandatory sabbath, but it is widely treated as a day when ordinary work slows and religious or social activity becomes more common.
Because months contain 31 days while the week contains 6 days:
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each month contains five full weeks plus one additional day
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the 31st day falls on the same weekday as the 1st day
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each new month therefore begins one weekday later than the previous month began
This predictable rotation makes long-term date calculations straightforward. In practice, this means that if the first day of one month falls on Primus, the next month will begin on Secundus, the following on Tertius, and so on through the six-day cycle before repeating.
As with the months, many regions use local-language equivalents in casual speech, translating the day numbers into their own languages. However, the High Speech names remain universally understood and commonly appear in written records.
The Moon
Aletheia has a single moon.
The lunar synodic period is approximately 31.1 days.
Because months are 31 days, the lunar cycle does not remain fixed to the calendar. The full moon drifts gradually across the months over time.
This produces:
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seasonal full moons
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shifting religious observances
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regional traditions tied to moonlight
The moon matters symbolically and ritually, but the civic calendar remains solar.
The Mid-Summer Festival
The largest shared celebration across Aletheia occurs at mid-year.
Astronomical Anchor
The year’s midpoint falls within Solis.
The festival begins on:
The first full moon after the midpoint of Solis
This means the festival usually begins between late Solis and early Aestivus. It shifts slightly year to year due to the lunar cycle.
Duration
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Six days in a normal year
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Seven days in a leap year
The Leap Day, when present, is inserted after the third day of the festival.
Nature of the Festival
There are no universally mandated named days.
Across most regions, the festival involves:
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feasting
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games and contests
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public gatherings
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fairs and performances
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temple ceremonies
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guild announcements
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marriages and oath-taking
The tone is celebratory by default.
However, emphasis varies:
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Some regions highlight agricultural gratitude.
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Some emphasize civic pride.
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Some incorporate solemn remembrance tied to historical trauma.
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Temple-dominant areas may add formal rites.
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Urban centers often extend markets and competitions.
Participation is intense but not universally compulsory. Agricultural labor and essential services continue where necessary.
Institutional Role
The calendar predates the Cataclysm and was quickly resumed afterward.
Its survival reflects:
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administrative stability
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agricultural necessity
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cultural continuity
Temple astronomers typically announce the exact start of the Mid-Summer Festival each year, though the full moon is visible to all.
There is no single global authority enforcing the calendar, but deviation is rare because the system is simple, functional, and widely accepted.
Summary
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Day: 25 hours
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Solar Year: 372.2 days
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Civic Year: 372 days (373 every fifth year)
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Leap Rule: +1 day every 5 years
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Months: 12 × 31 days
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Week: 6 days
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Moon: ~31.1-day cycle, not month-aligned
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Mid-Summer Festival: Begins on first full moon after mid-Solis; 6 days (7 in leap years)
The Calendar of Aletheia is not perfectly tidy, nor is it chaotic. It reflects a world that values continuity, practicality, and seasonal alignment — and one that remembers the importance of maintaining balance.
title: Simple Weekday Calculation Rule
Because each month contains **31 days**, the first day of each new month advances **one weekday** through the six-day cycle.
This means:
> **weekday = (month offset + day − 1) mod 6**
Where:
- **month offset** = number of months since the start of the year
- **day** = day of the month
- weekday values correspond to
`0 Primus, 1 Secundus, 2 Tertius, 3 Quartus, 4 Quintus, 5 Deorum`
Leap Day does **not** advance the weekday cycle because it lies outside the week.
This pattern repeats each year unless a leap year occurs.
In a **leap year**, the extra Leap Day shifts all subsequent weekdays by **one additional day**.
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