Calendar

A is a system of organizing days. This is done by giving names to periods of time, typically days, weeks, months and years. A date is the designation of a single, specific day within such a system. A calendar is also a physical record (often paper) of such a system. A calendar can also mean a list of planned events, such as a court calendar or a partly or fully chronological list of documents, such as a calendar of wills.

Periods in a calendar (such as years and months) are usually, though not necessarily, synchronized with the cycle of the sun or the moon. The most common type of pre-modern calendar was the lunisolar calendar, a lunar calendar that occasionally adds one intercalary month to remain synchronized with the solar year over the long term.

Túzyn Reckoning
On the calendar used through much of the world is. The calendar now used throughout takes the foundation of the  as its Year 1. Túzyn Reckoning was devised in 130 by Túzyn of Mèlderýn, a court astronomer in the reign of, but was backdated to the founding of the kingdom. Throughout the last six centuries, this calendar has gradually been adopted by all Hârnic states, replacing a multitude of calendars, most too inaccurate to be useful. The and the, however, still retain their own calendars. Most uncivilized tribes use some form of sun/moon reckoning. Dates given in Tuzyn Reckoning may be preceded or followed by the symbol “SB TR.” Historians have come to use “SB BT” (Before Túzyn) to identify years before the foundation of Mèlderýn. The Túzyn calender has 12 lunar months, each of 30 days, for a total of 360 days in one Hârnic year.

A new moon occurs on the thirtieth day of each month and a full moon on the fifteenth. Both are holidays in most parts of Hârn. Other holidays are scattered throughout the year based on planting, harvesting, and religious festivals; these vary by locale. The first day of the year is deemed the beginning of spring. It was originally set to coincide with the vernal equinox but an error of nearly one day has since developed.

Gregorian
On the Gregorian calendar is the de facto international standard and is used almost everywhere in the world for civil purposes. The widely used solar aspect is a cycle of leap days in a 400-year cycle designed to keep the duration of the year aligned with the solar year. There is a lunar aspect which approximates the position of the moon during the year, and is used in the calculation of the date of Easter.

Each Gregorian year has either 365 or 366 days (the leap day being inserted as 29 February), amounting to an average Gregorian year of 365.2425 days (compared to a solar year of 365.2422 days). It was introduced in 1582 as a refinement to the Julian calendar which had been in use throughout the European Middle Ages, amounting to a 0.002% correction in the length of the year.

During the Early Modern period, however, its adoption was mostly limited to Roman Catholic nations, but by the 19th century, it became widely adopted worldwide for the sake of convenience in international trade. The last European country to adopt the reform was Greece, in 1923.

The calendar epoch used by the Gregorian calendar is inherited from the medieval convention established by Dionysius Exiguus and associated with the Julian calendar. The year number is variously given as AD (for Anno Domini) or CE (for Common Era or Christian Era).

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