Since the influence of Sonndalin spread throughout the world, a single standard calendar has been in effect. It was established by the dwarves and is based on their old calendar, though modifications were made to remove all references to the old dwarven pantheon and to accomodate modern ideas and astronomical knowledge. Month names were chosen to match the changing seasons of a year as felt in the northern hemisphere.
The current calendar splits history into several ages, each marked by an event of unparalleled importance:
- The First Age was marked by the birth of the Earth, whether by the will of as-yet unknown deities or by natural processes. It saw the rise of life on Earth and the eventual appearance of sentience. Its duration is currently hotly debated.
- The Second Age began when the great city of Midian was founded by the dwarf chieftain Thorazil the Great. It lasted 3,423 years, though the city still exists.
- The Third Age began when immortality was first achieved by Mordun and Zahar. It saw the rise of the other Elder Gods and, centuries later, the infestation of the world by undead creatures due to the ripping in various places of the barrier between the Earth and the Undearth.
An Earth year lasts approximately 365 days. The first day of each year is called New Year, and the remaining days are grouped into thirteen 28-day-long months as follows:
- Northern winter begins on New Year, one day before wintermoon 1.
- Blackmoon 17 is the shortest day of the year in the northern hemisphere.
- Birthmoon 7 marks the beginning of northern spring.
- Clearmoon 14 marks the beginning of northern summer.
- Glaremoon 3 is the longest day of the year in the northern hemisphere.
- Rosemoon 21 marks the beginning of northern autumn.
A small correction --in the form of Withermoon lasting 29 days-- must be made every four centuries or so because a year lasts approximately 365.0025 days.
Shorter units of time are defined as follows:
- A day is exactly 24 hours long.
- An hour is exactly 60 minutes long.
- A minute is exactly 60 seconds long.