Gregorian versus Julian calendar
The Gregorian calendar is currently commonly used, based on the already-specified principle of leap year management. The Gregorian calendar was introduced by Pope Gregory XIII in 1582. The aim was to apply date shift properly (one year does not take exactly 365.25 days, so the leap year should not be applied once in four years generally), respecting the Earth’s speed. This way, proper day mapping over the centuries can be ensured.
The Julian calendar was established in 46 BC by Julius Caesar as an update to the Roman calendar, which used 29 days for most months, by introducing an extra intercalary month between February and March. Note that this intercalary month is not applied every year but only for those years that are marked as intercalary years). It was used up to 1582. Then, it was replaced by the Gregorian calendar. The main difference in these calendars is related to the year definition. The Julian calendar has two types of year &...
