Calendar world for civil purposes. It is a purely solar calendar, with a cycle of leap days in a 400-year cycle designed to keep the duration of the year aligned with the solar year. 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.
Middle-earth calendar our own (Gregorian). It has a week of seven days. The calendar year has 365 days (except in leap-years), and twelve months ("astar"): ten with 30 days and two with 31. Unlike the Gregorian calendar, the King's Reckoning has some days outside the months. These special monthless days, a feature borrowed from Elvish Calendars, were generally holidays. Two of these special days were the pair which book-ends the year; thus, in the King's Reckoning, the last month of the year is followed by "mettarë", the last day of the year; this is then followed "yestarë", New Year's Day, which is