Sages and historians measure Adnati’s history in terms of Eras, Epochs, and Ages.
Eras
Eras are the broadest historical unit of time, measuring hundreds of millions and even billions of years. Each Era may have multiple subunits known as Epochs. Historians divide Adnati’s history into three eras. The First Era covers the period of time when the earth was created. The Second Era covers the period of time when life on Adnati emerged, both plants and animals. The Third Era covers the emergence of intelligent hominid life, both on the surface and in the Underdark, including humans, elves, dwarves, orcs, goblins, and others.
Epochs
Epochs are a unit of historical time that can last tens or even hundreds of millions of years. Epochs are a subdivision of Eras and can be subdivided into multiple Ages.
Ages
Ages are the smallest of the broad units of historical measurement. They are a subdivision of Epochs, and each Epoch may be divided into several Ages. Each Age can last thousands or even tens of thousands of years.
Years
Years are the measurement of how long it takes Adnati to cycle through all four seasons. On the Common Calendar, the year begins on the Winter Solstice and cycles through Winter, Spring, Summer, and Autumn before returning to the Winter Solstice, a cycle that lasts 362 days.
Each year is subdivided into twelve months, almost all of them lasting thirty days. The first day of the year, the Winter Solstice, is considered a “null” day and is not considered to be part of any month. It falls between the end of Atraradaans, the twelfth month of the year, and the beginning of Elapidaans, the first month of the next year. The remaining of the 362 days is the Summer Solstice, which is tacked onto the end of Altadaans, the third month of Spring and of the calendar year, which gives Altadaans thirty-one days, one more than the other months.
Each month has three weeks, each lasting ten days. Each week typically has two weekend days of rest, as well as two half-days of work.