History of mathematics the Roman Kingdom and included 356 days plus a leap year every other year. In contrast, the lunar calendar of the Republican era contained 355 days, roughly ten-and-one-fourth days shorter than the solar year, a discrepancy that was solved by adding an extra month into the calendar after the 23rd of February. This calendar was supplanted by the Julian calendar, a solar calendar organized by Julius Caesar (100–44 BC) and devised by Sosigenes of Alexandria to include a leap day every four years in a 365-day cycle. This calendar, which contained an error of 11 minutes and 14 seconds, was
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