Gregoriánnaptárat

Gregoriánnaptárat is a calendar system used by some Eastern Orthodox churches. It is named after Pope Gregory XIII and is similar to the Gregorian calendar used internationally. However, it differs in the way it accounts for daylight saving time and its calculations for leap years.

The reason for the creation of Gregoriánnaptárat was to replace the Julian calendar, which had been in use since the 1st century AD. The Julian calendar had a leap year almost every four years, but this resulted in an extra day over the course of 400 years, causing the calendar to drift away from the actual solar year. To correct this error, Pope Gregory XIII introduced a new calendar that omitted 10 days from the month of October in 1582.

In the Gregoriánnaptárat, the Julian calendar's leap year rule is essentially maintained, though with certain corrections. The new calendar reduced the error to about 1 day every 3,300 years. However, when converting to the Gregoriánnaptárat from the Julian calendar, the years from 1900 to 2099 that are divisible by 4, but not by 100, are also leap years according to the Gregoriánnaptárat.

Despite its widespread use internationally, the Gregoriánnaptárat is not universally accepted. Some Eastern Orthodox churches continue to use the Julian calendar, which is 13 days behind the Gregoriánnaptárat. This can cause confusion when Eastern Orthodox churches interact with international communities, particularly when planning holidays and events.