JULIAN CALENDAR, PREDOMINANT FROM 45 BC TO 1582

An old year has passed away and a new tear has just arrived, and The Grandma has been reading about the Julian calendar to commemorate this January, 1.

The Julian calendar, proposed by Roman consul Julius Caesar in 46 BC, was a reform of the Roman calendar.

It took effect on 1 January 45 BC, by edict. It was designed with the aid of Greek mathematicians and astronomers such as Sosigenes of Alexandria.

The calendar became the predominant calendar in the Roman Empire and subsequently most of the Western world for more than 1,600 years until 1582, when Pope Gregory XIII promulgated a minor modification to reduce the average length of the year from 365.25 days to 365.2425 days and thus corrected the Julian calendar's drift against the solar year.

Worldwide adoption of this revised calendar, which became known as the Gregorian calendar, took place over the subsequent centuries, first in Catholic countries and subsequently in Protestant countries of the Western Christian world.

The Julian calendar is still used in parts of the Eastern Orthodox Church and in parts of Oriental Orthodoxy as well as by the Berbers.

The Julian calendar has two types of years: a normal year of 365 days and a leap year of 366 days. They follow a simple cycle of three normal years and one leap year, giving an average year that is 365.25 days long. That is more than the actual solar year value of 365.24219 days (the current value, which varies), which means the Julian calendar gains a day every 128 years.

For any given event during the years from 1901 to 2099 inclusive, its date according to the Julian calendar is 13 days behind its corresponding Gregorian date.

More information: Time and Date

The ordinary year in the previous Roman calendar consisted of 12 months, for a total of 355 days. In addition, a 27- or 28-day intercalary month, the Mensis Intercalaris, was sometimes inserted between February and March. This intercalary month was formed by inserting 22 or 23 days after the first 23 days of February; the last five days of February, which counted down toward the start of March, became the last five days of Intercalaris. The net effect was to add 22 or 23 days to the year, forming an intercalary year of 377 or 378 days. Some say the mensis intercalaris always had 27 days and began on either the first or the second day after the Terminalia (23 February).

According to the later writers Censorinus and Macrobius, the ideal intercalary cycle consisted of ordinary years of 355 days alternating with intercalary years, alternately 377 and 378 days long. In this system, the average Roman year would have had 366+1⁄4 days over four years, giving it an average drift of one day per year relative to any solstice or equinox.

Macrobius describes a further refinement whereby, in one eight-year period within a 24-year cycle, there were only three intercalary years, each of 377 days (thus 11 intercalary years out of 24). This refinement averages the length of the year to 365.25 days over 24 years.

In practice, intercalations did not occur systematically according to any of these ideal systems, but were determined by the pontifices. So far as can be determined from the historical evidence, they were much less regular than these ideal schemes suggest. They usually occurred every second or third year, but were sometimes omitted for much longer, and occasionally occurred in two consecutive years.

The Roman calendar began the year on 1 January, and this remained the start of the year after the Julian reform. However, even after local calendars were aligned to the Julian calendar, they started the new year on different dates.

The Julian calendar has been replaced as the civil calendar by the Gregorian calendar in all countries which officially used it. Turkey switched (for fiscal purposes) on 16 February/1 March 1917.

Russia changed on 1/14 February 1918. Greece made the change for civil purposes on 16 February/1 March 1923, but the national day (25 March), was to remain on the old calendar. Most Christian denominations in the west and areas evangelised by western churches have made the change to Gregorian for their liturgical calendars to align with the civil calendar.

A calendar similar to the Julian one, the Alexandrian calendar, is the basis for the Ethiopian calendar, which is still the civil calendar of Ethiopia. Egypt converted from the Alexandrian calendar to Gregorian on 1 Thaut 1592/11 September 1875.

During the changeover between calendars and for some time afterwards, dual dating was used in documents and gave the date according to both systems. In contemporary as well as modern texts that describe events during the period of change, it is customary to clarify to which calendar a given date refers by using an O.S. or N.S. suffix (denoting Old Style, Julian or New Style, Gregorian).

More information: Calendarr

Calendars and clocks exist to measure time,
 but that signifies little
because we all know that an hour can seem
as eternity or pass in a flash,
according to how we spend it.

Michael Ende