person holding calendar at JanuaryPhoto by <a href="" rel="nofollow">Brooke Lark</a> on <a href="" rel="nofollow">Unsplash</a>

The Julian calendar is an ancient calendar system that was introduced by Julius Caesar in 45 BCE. It was widely used in Europe and the Western world until it was replaced by the Gregorian calendar in the late 16th century. Despite its discontinuation as the official calendar, the Julian calendar is still observed in some countries and communities, particularly for religious and cultural purposes.

Understanding the Julian Calendar

The Julian calendar is a solar calendar that consists of 365 days in a year, with an additional day added every four years to account for the leap year. This extra day, known as the leap day, is inserted at the end of February. The Julian calendar follows a 12-month system, with each month having either 30 or 31 days, except for February, which has 28 days in a common year and 29 days in a leap year.

While the Julian calendar was widely used for many centuries, it eventually fell out of sync with the solar year due to a slight miscalculation in the length of the year. This discrepancy led to the adoption of the Gregorian calendar, which is the calendar system used by most countries today.

Holidays on the Julian Calendar

Although the Julian calendar is no longer the official calendar, it is still used by some Eastern Orthodox churches and communities. These groups continue to celebrate religious holidays according to the Julian calendar, which often differ from the dates observed by Western Christianity.

One of the most notable holidays celebrated on the Julian calendar is Christmas. While the majority of Christians celebrate Christmas on December 25th according to the Gregorian calendar, Eastern Orthodox Christians who follow the Julian calendar celebrate Christmas on January 7th. This date corresponds to December 25th on the Julian calendar.

Another significant holiday celebrated on the Julian calendar is Easter. Eastern Orthodox Christians calculate the date of Easter based on the Julian calendar, which can sometimes result in a different date than the one observed by Western Christianity. This means that Easter is often celebrated on different dates by Eastern Orthodox Christians and other Christian denominations.

In addition to Christmas and Easter, there are several other holidays and feast days that are observed on the Julian calendar. These include Epiphany, Palm Sunday, Ascension Day, Pentecost, and various saints’ days. The dates of these holidays may vary slightly from year to year due to the difference between the Julian and Gregorian calendars.

Transition to the Gregorian Calendar

The transition from the Julian calendar to the Gregorian calendar took place at different times in different countries. The Catholic countries of Europe adopted the Gregorian calendar in 1582, while Protestant and Orthodox countries made the transition at later dates.

As a result of the calendar change, several days were skipped to align the calendar with the solar year. In Catholic countries, the day after October 4, 1582, was declared as October 15, 1582, effectively skipping 10 days. This adjustment was made to correct the accumulated discrepancy between the Julian calendar and the solar year.

However, not all countries immediately adopted the Gregorian calendar. Some Orthodox countries, such as Russia, continued to use the Julian calendar until the early 20th century. Russia switched to the Gregorian calendar in 1918, which resulted in a difference of 13 days between the two calendars.


The Julian calendar, despite being replaced by the Gregorian calendar as the official calendar system, still holds significance for certain religious and cultural communities. It is observed by Eastern Orthodox churches and is associated with specific holidays and celebrations, such as Christmas and Easter. Understanding the Julian calendar and its holidays provides insight into the rich history and diversity of calendar systems that have shaped our world.