But there are other calendars that follow Lunar calendars to a T, such as the Islamic calendar, which is made up of 13 months. Each month in this calendar lasts for a single lunar cycle.

Leap years were first introduced with the Julian calendar in 46 BC by Julius Caesar, who added an extra day to February every four years, based on the work of the astronomer Sosigenes, to account for ...

Eastern Orthodox churches use the Julian calendar, which can place the date of Easter anywhere between April 4 and May 8 when it's converted back to the Gregorian calendar. This year, the Eastern ...

The solar calendar had the same number of days as the Julian calendar that was used in Europe in the same time period, but the Aztecs had a different method for subdividing the year. Their ...

There are 52.143 weeks in a regular year and 52.286 in a leap year. ... The Julian calendar calculated the length of the year at 365.25 days, so it added an extra day every four years.

Prior to the Gregorian and even Julian calendars, Roman King Numa Pompilius (715-673 BC) set about creating a calendar with equal-length months, the University of Chicago said.

Eastern Orthodox churches use the Julian calendar, which can place the date of Easter anywhere between April 4 and May 8 when it's converted back to the Gregorian calendar. This year, the Eastern ...