when were january and february added to the calendar
Roman calendar Plutarch believed Numa was responsible for placing January and February first in the calendar;[15][16] Ovid states January began as the first month and February the last, with its present order owing to the Decemvirs.[22][23] W. Warde Fowler believed the Roman priests continued to treat January and February as the last months of the calendar throughout the Republican period.[24]
Leap year In the Gregorian calendar, the standard calendar in most of the world, most years that are multiples of 4 are leap years. In each leap year, the month of February has 29 days instead of 28. Adding one extra day in the calendar every four years compensates for the fact that a period of 365 days is shorter than a tropical year by almost 6 hours.[4] Some exceptions to this basic rule are required since the duration of a tropical year is slightly less than 365.25 days. The Gregorian reform modified the Julian calendar's scheme of leap years as follows: