Exactly 100 years ago, the Russian Republic lived the first day of the new style. Due to the transition from the Julian calendar to the more accurate Gregorian, which was adopted in most European countries back in the 17th century, the first 13 days of February 1918 simply fell out of the calendar, and after January 31, February 14 immediately came. This not only helped to synchronize the national calendar with the calendars of other countries, but also led to the fact that the day of the Great October Revolution in the Soviet Union, despite the name, began to be celebrated on November 7, Pushkin's birthday in June, although he was born, as you know, May 26, and in mid-January, an incomprehensible holiday appeared - the Old New Year. At the same time, the Russian Orthodox Church still uses the Julian calendar, so, for example, Orthodox and Catholics celebrate Christmas on different days.

On January 26, 1918, a decree was adopted, according to which the young Soviet Russian Republic switched to the Gregorian calendar generally accepted in Europe. This led not only to a shift in dates, but also to some amendments in determining leap years. In order to understand where the discrepancy between the two calendars comes from, let us first consider the natural processes that were used in their development.

Astronomy and calendar

The most common calendars are based on the ratio of the times of three cyclic astronomical processes: the rotation of the Earth around its axis, the rotation of the Moon around the Earth, and the rotation of the Earth itself around the Sun. These three processes lead to periodic changes that are clearly visible on Earth: the change of day and night, the change in the phases of the moon and the alternation of the seasons, respectively. The ratio of the durations of these time intervals underlies the overwhelming number of calendars used by mankind. It is clear that there are other astronomical events visible to humans on Earth that occur with convenient regularity (for example, in ancient Egypt, the ascent of Sirius was observed, which had the same annual cycle), but using them to develop a calendar is still rather an exception.

Of the three indicated intervals, from an astronomical point of view, it is easiest to deal with the shortest of them - the length of the day. Now, for the period of time, on the basis of which, in particular, calendars are compiled, they take the average solar day - that is, the average period of time during which the Earth rotates around its axis relative to the center of the Sun. Solar days are because the center of the Sun is used as a reference point, and it is necessary to average a day over a year due to the fact that, due to the ellipticity of the Earth's orbit and its perturbation by other celestial bodies, the period of revolution of our planet changes over the course of the year, and the longest and most short days differ from each other by almost 16 seconds.

A method for determining the duration of a solar day, which are calculated by changing the orientation of the Earth relative to the initial position (1) not by a full turn of 360 degrees to position (2), but by one revolution relative to the center of the Sun to position (3)

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The second of the time intervals needed for the calendar is the year. Of several possible options for determining a gap of one year, when compiling a calendar, a seasonal cycle is used, which can be observed when looking at the position of the Sun in the sky from Earth - the so-called tropical year. It is determined by the change in the ecliptic coordinates of the Sun, and one annual cycle corresponds to a change of 360 degrees in its ecliptic longitude (that is, its longitudinal position on the celestial sphere, measured from the vernal equinox, at which the plane of the Earth's rotation around the Sun and the Earth's equatorial plane intersect). At the same time, the length of the year may vary slightly depending on the choice of the starting point, and, as a rule, the point of the vernal equinox is chosen as the starting position, because for it the error in determining the length of the year is minimal.

At the heart of the solar calendars most common now (including the Julian and Gregorian) is the ratio of the time of the daily and annual periods. This ratio, that is, the duration of the tropical year in days, is, of course, not an integer and amounts to 365.2422. And how close the calendar can adjust to this value directly depends on its accuracy.

It is worth noting that despite the fact that the duration of one tropical year is almost constant, due to small perturbations in the Earth's orbit, it still changes slightly. These perturbations are associated with the influence of the celestial bodies closest to the Earth, primarily Mars and Venus, they are all periodic and have an amplitude of 6 to 9 minutes. The period of each of the perturbations is two or three years, which together give a 19-year nutation cycle. In addition, the duration of the tropical year does not coincide with the time of the Earth's revolution around the Sun (the so-called sidereal year). This is due to the precession of the earth's axis, which leads to a difference that is now about 20 minutes (the length of a sidereal year in days is 365.2564).

The third of the periods of time used for compiling calendars is the synodic month. It is measured as the time between two identical phases of the moon (for example, new moons) and averages 29.5306 solar days. The phases of the moon are determined by the mutual position of the three celestial bodies - the Earth, the Moon and the Sun and, for example, do not correspond to the periodicity of the position of the Moon on the celestial sphere relative to the stars. Also, like the tropical year, the synodic month varies greatly in length.

Lunar calendars based on the phases of the moon were used quite widely, but in most cases they were supplanted by solar or solar-lunar calendars. This is explained both by the inconvenience of using lunar calendars due to noticeable variations in the length of the month, and by the natural binding of human activity to seasonal weather changes, which can be associated with the position of the Sun in the sky, but not with the phase of the Moon. Today, lunar calendars are used mainly to determine the dates of religious holidays. In particular, the Muslim calendar is lunar, and the dates of Old Testament Christian holidays, especially Easter, are also determined by the lunar calendar.

Any calendar is based on attempts to link at least two of these time intervals. But since any of these ratios cannot be represented as an ordinary fraction, it is impossible to compile an absolutely accurate calendar. This problem can be solved in a relatively simple way, without resorting to any calendars at all, but using only one interval, for example, the length of a day. For example, astronomers who simply count the days starting from a certain point in the past (according to the modern calendar, this point corresponds to noon on November 24, 4714 BC) suggest doing this. In this case, any time point is determined by the Julian date - a fractional number that corresponds to the number of days that have passed since the start of the reference.

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In the figure above: A method for determining the ecliptic coordinates of a celestial body (for example, the Sun) on the celestial sphere. They are measured from the vernal equinox.

Julian calendar

But counting time only by days is still not very convenient, and I want to have time intervals on a larger scale at hand. Even realizing that no calendar will allow us to describe with absolute accuracy the relationship between the duration of a solar day, a tropical year, and a synodic month, one can achieve satisfactory accuracy from it. It is precisely in the degree of accuracy in describing the ratio of two of these three intervals that the difference between the Julian calendar and the Gregorian one lies.

Both of these calendars are solar, they are designed to link the length of the mean solar day and the tropical year. We know that from an astronomical point of view, the length of a tropical year is approximately 365.2422 days. To make a calendar, this number must be somehow described so that in each calendar year there is an integer number of days. The easiest way to do this is by varying the length of the year.

The roughest acceptable rounding gives 365.25 days, and it is on this that the Julian calendar is built. If, with this rounding of the average length of the year, we divide the year into 365 days, then for every four years an error of one day will accumulate. It is from here that the structure of the calendar appears, in which every fourth year is a leap year, that is, it includes one day more than usual. The full cycle of such a calendar is only four years, which makes it very easy to use.

The Julian calendar was developed by Alexandrian astronomers, named after Julius Caesar and put into use in 46 BC. It is interesting that initially an extra day in a leap year was added not by introducing a new date - February 29, but by duplicating February 24.

Of course, the Julian calendar is far from the first version of the solar calendar. So, the ancient Egyptian solar calendar served as the basis for all modern solar calendars. It was counted according to the position of the rising Sirius in the sky and included 365 days. And although the Egyptians understood that with such a counting system, for example, a shift in the dates of the solstices and equinoxes occurs very quickly, for convenience, the length of the year did not change. Therefore, every four years there was a shift by one day, and after 1460 years (this interval was called the Great Year of Sothis), the year returned to its original position.

At the same time, in Ancient Rome itself, the Julian calendar replaced the previously used Roman calendar, which consisted of ten months and included 354 days. To bring the length of the calendar year into line with the length of the tropical year, an extra month was added to the year every few years.

The Julian calendar turned out to be much more convenient than the Roman one, but it was still not very accurate. The difference between 365.2422 and 365.25 is still large, so the inaccuracy of the Julian calendar was noticed quite soon, primarily due to the shift in the date of the vernal equinox. By the 16th century, it had already moved 10 days from its initial position, established by the Council of Nicaea in 325 on March 21. Therefore, in order to improve the accuracy of the calendar, it was proposed to amend the existing system of leap years.

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Graph of the shift in the time of the summer solstice depending on the year according to the Gregorian calendar. Years are plotted along the abscissa, and the calculated actual time of the summer solstice in calendar notation is plotted along the ordinate (a quarter of a day corresponds to six hours).

Gregorian calendar

The new calendar was put into use by Pope Gregory XIII, who issued the bull Inter gravissimas in 1582. To more accurately match the calendar year to the tropical number of leap years in the new Gregorian calendar compared to the Julian decreased by three for every 400 years. Therefore, leap years ceased to be those whose serial numbers are completely divisible by 100, but are not divisible by 400. That is, 1900 and 2100 are not leap years, but, for example, 2000 was a leap year.

Taking into account the introduced amendments, the duration of one year in days according to the Gregorian calendar was 365.2425, which is already much closer to the required value of 365.2422 compared to what the Julian calendar offered. As a result of the proposed amendments, a difference of three days accumulates between the Julian and Gregorian calendars for 400 years. At the same time, the correction was carried out according to the shift of the day of the vernal equinox in relation to the date established by the Council of Nicaea - March 21, 325, so it was only 10 days (the next day after October 4 in 1582 was immediately October 15), and the zero difference between the calendars does not correspond to the first century AD, and the third.

The transition to a more accurate Gregorian calendar in Europe occurred gradually. First, in the 80s of the 16th century, all Catholic countries switched to the Gregorian calendar, and during the 17th and 18th centuries, gradually Protestant states. Despite the fact that the reform of Gregory XIII was a measure of the Counter-Reformation, symbolically subordinating calendar time to the bull of the Roman pontiff, its objective advantages were too obvious to be resisted for a long time on religious grounds.

In Russia, the process of transition to an updated calendar was somewhat delayed: until 1700, when most European countries already lived according to the Gregorian calendar, the Byzantine chronology was still adopted in the Russian kingdom. In terms of the definition of leap years, the Byzantine calendar, developed in the 7th century, corresponded to the Julian calendar, but differed in the names of the months, the date of the beginning of the year (September 1) and the reference point of the chronology. If the Julian and Gregorian calendars consider January 1 of the year in which Jesus Christ was born, then in the Byzantine version, the time is considered “from the creation of the world”, supposedly in 5509 BC. (Note that in determining the exact year of the birth of Christ, a mistake of several years was probably made, due to which, according to the Julian calendar, this should not be the first year of our era, but 7-5 years BC).

Russia was converted to the Julian calendar by Peter the Great in 1700. On the one hand, he saw the need to "synchronize" the historical time of Russia with the European one, on the other hand, he had a deep distrust of the "papist" calendar, not wanting to introduce a "heretical" Paschal. True, the Old Believers did not accept his reforms and still count the dates according to the Byzantine calendar. The New Believer Orthodox Church switched to the Julian calendar, but at the same time, until the beginning of the 20th century, it opposed the introduction of a more accurate Gregorian.

Due to the practical inconveniences that arose in the conduct of international affairs, as a result of the discrepancy between the calendars adopted in Europe and the Russian Empire, the issue of switching to the Gregorian calendar was raised, especially during the 19th century, more than once. For the first time, such a question was discussed during the liberal reforms of Alexander I, but then it never reached the official level. The problem of the calendar was raised more seriously in 1830, a special committee at the Academy of Sciences was even assembled for this, but as a result, Nicholas I chose to abandon the reform, agreeing with the arguments of the Minister of Education Karl Lieven about the unpreparedness of the people to switch to another calendar system due to insufficient education and possible indignations.

"Decree on the introduction of the Western European calendar in the Russian Republic"

The next time a serious commission about the need to switch to the Gregorian calendar in the Russian Empire was collected at the very end of the 19th century. The commission was formed under the Russian Astronomical Society, but, despite the participation of prominent scientists in it, in particular Dmitri Mendeleev, it was still decided to abandon the transition due to the insufficient accuracy of the Gregorian calendar.

At the same time, the commission considered the issue of switching both to the Gregorian calendar and to an even more accurate version developed by astronomer Johann Heinrich von Medler, a professor at Dorpat University, in 1884. Medler proposed to use a calendar with a 128-year cycle containing 31 leap years. The average length of a year in days according to such a calendar will be 365.2421875, and an error of one day accumulates over 100,000 years. However, this project was not accepted either. According to historians, the opinion of the Orthodox Church played a significant role in the rejection of reforms.

Only in 1917, after the October Revolution and the separation of church and state, did the Bolsheviks decide to switch to the Gregorian calendar. By that time, the difference between the two calendars had already reached 13 days. Several options were proposed for the transition to the new style. The first of them involved a gradual transition over 13 years, in which each year an amendment would be made in one day. However, in the end, the second, more radical, option was chosen, according to which, in 1918, the first half of February was simply canceled, so that after January 31, February 14 immediately came.

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Graph of the offset time of the vernal equinox according to the New Julian calendar. Years are plotted along the abscissa, and the calculated actual time of the vernal equinox in calendar notation (a quarter of a day corresponds to six hours) is plotted along the ordinate. The blue vertical line marks the year 1923, when the calendar was designed. The time period before this date is considered according to the proleptic New Julian calendar, which extends the dating to an earlier time.

Julian calendar and the Orthodox Church

The Russian Orthodox Church still continues to use the Julian calendar. The main reason why she refuses to switch to the Gregorian calendar is the linking of a number of church holidays (primarily Easter) to the lunar calendar. To calculate the date of Easter, the easter system is used, which is based on a comparison of lunar months and tropical years (19 tropical years are quite exactly equal to 235 lunar months).

The transition to the Gregorian calendar, according to representatives of the Russian Orthodox Church, will lead to serious canonical violations. In particular, in some cases, when using the Gregorian calendar, the date of the Catholic Easter turns out to be earlier than the Jewish date or coincides with it, which contradicts the Apostolic canons. After the transition to the Gregorian calendar, Catholics celebrated Easter four times before the Jews (all in the 19th century) and five times simultaneously with them (in the 19th and 20th centuries). In addition, Orthodox priests find other reasons not to switch to the Gregorian calendar, such as reducing the duration of some fasts.

At the same time, at the beginning of the 20th century, part of the Orthodox churches switched to the New Julian calendar - with amendments introduced by the Serbian astronomer Milutin Milanković (known primarily for describing climatic cycles). Milankovitch suggested that instead of subtracting three leap years every 400 years, subtract seven leap years every 900 years. Thus, the full cycle of the New Julian calendar is 900 years, which makes it even more accurate, but also more difficult to use, even in relation to the Gregorian.

Milankovitch's amendments lead to the fact that the date according to the New Julian calendar may differ from the Gregorian both up and down (in the foreseeable future - no more than one day). At the moment, the dates of the New Julian and Gregorian calendars coincide, and the nearest discrepancy between them will appear only in 2800.

The accuracy of the New Julian calendar leads to an error accumulation of one day in 43,500 years. This is much better than the Gregorian calendar (one day in 3280 years) and, of course, the Julian (one day in 128 years). But, for example, the already mentioned Medler amendments, which were also considered by the Russian Orthodox Church as an alternative to the Julian calendar, make it possible to achieve twice the accuracy (one day per 100 thousand years), even despite a much shorter cycle of 128 years.

Returning to the issue of dating the October Revolution and Pushkin's birthday, it is worth noting that they are dated according to the new style (that is, according to the Gregorian calendar), indicating the date in brackets according to the old (Julian) style. Similarly, they do in European countries to date even those events that occurred before the introduction of the Gregorian calendar, while using the so-called proleptic Gregorian calendar, that is, expanding the Gregorian chronology for the period up to 1582.

The difference between the dates of the Catholic and Orthodox Christmas is now fully consistent with the difference between the Julian and Gregorian calendars. Accordingly, after the year 2100, Orthodox Christmas will shift from January 7 to January 8, and the difference in dates will increase by one more day.

Alexander Dubov

Often, when reading a historical article about events that took place before 1918, we see such dates: "The Battle of Borodino took place on August 26 (September 7), 1812." Why two dates? Which one is correct? What is the difference? Why those brackets? Not one hundred, and even a thousand people annually puzzle over these questions. But in fact, everything is simple. We will save you, dear readers, from a lot of numbers and calculations, and explain everything “on the fingers”.

Well slow down, so slow down. The point is calendars. Julian calendar- this is the calendar according to which Russia lived until 1918. In February 1918, we switched to a "new" style - to Gregorian calendar. In Europe, it began to spread from the XVI century. and was introduced by order of Pope Gregory XIII (hence the Gregorian).

Sosigenes - Alexandrian astronomer, creator of the "Julian" calendar, adopted by Julius Caesar in 42 BC. Pope Gregory XIII - creator of the "Gregorian" calendar, adopted in 1582

Now let's remember a few rules, knowing which, you will no longer get confused in the dates:

1 rule: the dates of all events that occurred before 1918 are written according to the old style, and the date according to the new - Gregorian - calendar is given in brackets: August 26 (September 7), 1812.

2 rule: if a document written before 1918 fell into your hands, and, accordingly, devoid of conversion to a new style, you don’t need to go online - you can calculate it yourself. To do this, you need this label:

from 10/05/1582 to 02/18/1700 - add 10 days.

from 02/19/1700 to 02/18/1800 - add 11 days.

from 02/19/1800 to 02/18/1900 - add 12 days.

from 02/19/1900 to 02/01/1918 - add 13 days.

Let's check ourselves:

Tsar Fyodor Ioannovich was born on March 18, 1584 according to the Julian calendar. We look at the plate - you need to add 10 days. Total according to the Gregorian calendar, the birthday of Fedor Ioannovich is March 28, 1584.

But the Battle of Poltava took place on June 27, 1709. How much should be added? Already 11 days. Turns out July 8th.

The Julian calendar continues to be used by the Russian Orthodox Church. Civil chronology in Russia is based on the Gregorian calendar. So what is the correct way to write the dates of historical events? When did the Battle of Borodino take place - August 26 or September 7? There is only one answer, and there cannot be another: it is correct to write the date that corresponded to the current calendar at that time. That is - August 26th.

In the halls of the Historical Museum and the Museum of the Patriotic War of 1812, you can find documents with different dates and check yourself. As you can see, it's simple. Onward to the museum!

Different peoples, religious cults, astronomers tried to make the calculation of the inexorably current time both the most accurate and simple for any person. The starting point was the movement of the Sun, Moon, Earth, the location of the stars. There are dozens of calendars developed and used so far. For the Christian world, there were only two significant calendars used for centuries - Julian and Gregorian. The latter is still the basis of the chronology, which is considered the most accurate, not subject to the accumulation of errors. The transition to the Gregorian calendar in Russia occurred in 1918. With what it was connected, this article will tell.

From Caesar to the present day

The Julian calendar was named after this multifaceted personality. The date of its appearance is considered to be January 1, 45. BC e. by decree of the emperor. It's funny that the starting point has little to do with astronomy - this is the day the consuls of Rome take office. This calendar, however, was not born from scratch:

• The basis for it was the calendar of ancient Egypt, which has existed for centuries, in which there were exactly 365 days, the change of seasons.
• The second source for compiling the Julian calendar was the existing Roman one, where there was a division into months.

It turned out to be a fairly balanced, thoughtful way of visualizing the flow of time. It harmoniously combined ease of use, clear periods with astronomical correlation between the Sun, Moon and stars, known for a long time and influencing the movement of the Earth.

The appearance of the Gregorian calendar, completely tied to the solar or tropical year, is due to grateful humanity to Pope Gregory XIII, who indicated that all Catholic countries should switch to a new time on October 4, 1582. It must be said that even in Europe this process was neither shaky nor rough. So, Prussia switched to it in 1610, Denmark, Norway, Iceland - in 1700, Great Britain with all overseas colonies - only in 1752.

When did Russia switch to the Gregorian calendar?

Thirsty for everything new after everything was destroyed, the fiery Bolsheviks gladly gave the command to switch to a new progressive calendar. The transition to it in Russia took place on January 31 (February 14), 1918. The Soviet government had quite revolutionary reasons for this event:

• Almost all European countries have long since switched to this method of reckoning, and only the reactionary tsarist government suppressed the initiative of peasants and workers who were very prone to astronomy and other exact sciences.
• The Russian Orthodox Church was against such violent intervention, which violated the sequence of biblical events. And how can "sellers of dope for the people" be smarter than the proletariat armed with the most advanced ideas.

Moreover, the differences between the two calendars cannot be called fundamentally different. By and large, the Gregorian calendar is a modified version of the Julian. The changes are mainly aimed at eliminating, less accumulation of temporary errors. But as a result of the dates of historical events that happened long ago, the births of famous personalities have a double, confusing reckoning.

For example, the October Revolution in Russia happened on October 25, 1917 - according to the Julian calendar or according to the so-called old style, which is a historical fact, or on November 7 of the same year in a new way - Gregorian. It feels like the Bolsheviks carried out the October uprising twice - the second time for an encore.

The Russian Orthodox Church, which the Bolsheviks were not able to force to recognize the new calendar either by executions of clergy or by organized robbery of artistic values, did not deviate from the biblical canons, counting the passage of time, the onset of church holidays according to the Julian calendar.

Therefore, the transition to the Gregorian calendar in Russia is not so much a scientific, organizational event as a political one, which at one time affected the fate of many people, and its echoes are still heard today. However, against the backdrop of a fun game of "turn the time forward / backward by an hour", which is still not completely over, judging by the initiatives of the most active deputies, this is already just a historical event.

The Julian calendar was introduced by Julius Caesar in 46 BC. It was supposedly developed by Egyptian astronomers (Alexandrian astronomers led by Sosigen), but they named it precisely in his honor.
It acquired its final form in 8 AD.
The year began on January 1, since it was on this day that the elected consuls took office, and then everything, as we know, is 12 months, 365 days, sometimes 366.

It is this “sometimes” that distinguishes it from the Gregorian calendar.

Actually the problem is that the full revolution around the sun - a tropical year - the Earth makes in 365.24219878 days. The calendar has an integer number of days. It turns out that if there are 365 days in a year, then every year the calendar will go astray - go ahead by almost a quarter of a day.
In the Julian calendar, they did it simply - to correct the discrepancy, it was assumed that every fourth year would be a leap year ( annus bissextus) and will have 366 days. Thus, the average length of the year in the Julian calendar is 365.25, already much closer to the real tropical year.

But not close enough - now the calendar began to lag behind every year by 11 minutes 14 seconds. For 128 years, it will be a day. This leads to the fact that some dates associated with astronomical phenomena, for example, the astronomical spring equinox, begin to shift towards the beginning of the calendar year.

The discrepancy between the astronomical vernal equinox and the calendar, fixed on March 21, became more and more pronounced, and since the Easter holiday was tied to the vernal equinox, many in Catholic Europe believed that something had to be done about the problem.

Finally, Pope Gregory XIII got together and reformed the calendar, producing what we now know as the Gregorian calendar. The project was developed by Luigi Lilio, and according to him, in the future, only those secular years should be considered leap years, the number of hundreds of years of which is divisible by 4 (1600, 2000, 2400), while others will be considered simple. The error of 10 days accumulated since 8 AD was also eliminated, and according to the decree of the pope of February 24, 1582, it was established that for October 4, 1582, October 15 should come immediately.

In the new calendar, the average length of the year was 365.2425 days. The error was only 26 seconds, and the discrepancy per day has been accumulating for about 3300 years.

As they say, "well, to be more precise, we don't need to." Or, let's put it this way - these will already be the problems of our distant descendants. In principle, it would be possible to declare every year divisible by 4000 not to be a leap year, and then the average value of the year would be 365.24225, with an even smaller error.

Catholic countries switched to the new calendar almost immediately (you can’t argue against the pope), Protestant countries with a creak, one of the last was Great Britain, in 1752, and only Orthodox Greece held on until the very end, which adopted the Gregorian calendar only in 1929.

Now only some Orthodox churches adhere to the Julian calendar, for example, Russian and Serbian.
The Julian calendar continues to lag behind the Gregorian - by one day every hundred years (if the secular year is not divisible by 4 without a remainder), or by three days in 400 years. By the 20th century, this difference had reached 13 days.

The calculator below converts a date from the Gregorian calendar to the Julian calendar and vice versa.
How to use it - enter the date, the Julian calendar field displays the Julian calendar date as if the entered date belongs to the Gregorian calendar, and the Gregorian calendar field displays the Gregorian calendar date as if the entered date belongs to the Julian calendar.

I also note that before October 15, 1582, the Gregorian calendar did not exist in principle, therefore, it is meaningless to talk about Gregorian dates corresponding to earlier Julian dates, although they can be extrapolated into the past.

- a number system for long periods of time, based on the periodicity of the visible movements of celestial bodies.

The most common solar calendar is based on the solar (tropical) year - the time interval between two successive passages of the center of the Sun through the vernal equinox.

A tropical year is approximately 365.2422 mean solar days.

The solar calendar includes the Julian calendar, the Gregorian calendar, and some others.

The modern calendar is called the Gregorian (new style) and was introduced by Pope Gregory XIII in 1582 and replaced the Julian calendar (old style) that had been in use since the 45th century BC.

The Gregorian calendar is a further refinement of the Julian calendar.

In the Julian calendar, proposed by Julius Caesar, the average length of the year in the interval of four years was 365.25 days, which is 11 minutes 14 seconds longer than the tropical year. Over time, the onset of seasonal phenomena according to the Julian calendar fell on ever earlier dates. Particularly strong discontent was caused by the constant shift in the date of Easter, associated with the spring equinox. In 325, the Nicene Council issued a decree on a single date for Easter for the entire Christian church.

© Public Domain

© Public Domain

In the following centuries, many proposals were made to improve the calendar. The proposals of the Neapolitan astronomer and physician Aloysius Lilius (Luigi Lilio Giraldi) and the Bavarian Jesuit Christopher Clavius ​​were approved by Pope Gregory XIII. On February 24, 1582, he issued a bull (message) introducing two important additions to the Julian calendar: 10 days were removed from the 1582 calendar - after October 4, October 15 immediately followed. This measure made it possible to keep March 21 as the date of the vernal equinox. In addition, three out of every four century years were to be considered ordinary and only those divisible by 400 were leap years.

1582 was the first year of the Gregorian calendar, called the new style.

The Gregorian calendar was introduced at different times in different countries. Italy, Spain, Portugal, Poland, France, Holland and Luxembourg were the first to adopt the new style in 1582. Then in the 1580s it was introduced in Austria, Switzerland, Hungary. In the XVIII century, the Gregorian calendar began to be used in Germany, Norway, Denmark, Great Britain, Sweden and Finland, in the XIX century - in Japan. At the beginning of the 20th century, the Gregorian calendar was introduced in China, Bulgaria, Serbia, Romania, Greece, Turkey and Egypt.

In Russia, along with the adoption of Christianity (X century), the Julian calendar was established. Since the new religion was borrowed from Byzantium, the years were counted according to the Constantinople era "from the creation of the world" (for 5508 BC). By decree of Peter I in 1700, the European chronology was introduced in Russia - "from the Nativity of Christ."

December 19, 7208 from the creation of the world, when the reformation decree was issued, in Europe corresponded to December 29, 1699 from the birth of Christ according to the Gregorian calendar.

At the same time, the Julian calendar was preserved in Russia. The Gregorian calendar was introduced after the October Revolution of 1917 - from February 14, 1918. The Russian Orthodox Church, preserving traditions, lives according to the Julian calendar.

The difference between the old and new styles is 11 days for the 18th century, 12 days for the 19th century, 13 days for the 20th and 21st centuries, 14 days for the 22nd century.

Although the Gregorian calendar is quite consistent with natural phenomena, it is also not completely accurate. The length of the year in the Gregorian calendar is 26 seconds longer than the tropical year and accumulates an error of 0.0003 days per year, which is three days in 10 thousand years. The Gregorian calendar also does not take into account the slowing of the Earth's rotation, which lengthens the day by 0.6 seconds per 100 years.

The modern structure of the Gregorian calendar also does not fully meet the needs of public life. Chief among its shortcomings is the variability of the number of days and weeks in months, quarters and half-years.

There are four main problems with the Gregorian calendar:

- Theoretically, the civil (calendar) year should have the same duration as the astronomical (tropical) year. However, this is impossible because the tropical year does not contain an integer number of days. Because of the need to add extra days to the year from time to time, there are two types of years - ordinary and leap years. Since a year can start on any day of the week, this gives seven types of common years and seven types of leap years, for a total of 14 types of years. For their full reproduction, you need to wait 28 years.

— The length of the months is different: they can contain from 28 to 31 days, and this unevenness leads to certain difficulties in economic calculations and statistics.|

Neither regular nor leap years contain an integer number of weeks. Half-years, quarters and months also do not contain a whole and equal number of weeks.

- From week to week, from month to month and from year to year, the correspondence of dates and days of the week changes, so it is difficult to establish the moments of various events.

In 1954 and 1956, the drafts of the new calendar were discussed at the sessions of the UN Economic and Social Council (ECOSOC), but the final decision on the issue was postponed.

In Russia, the State Duma was proposing to return the Julian calendar to the country from January 1, 2008. Deputies Victor Alksnis, Sergey Baburin, Irina Savelyeva and Alexander Fomenko proposed to establish a transitional period from December 31, 2007, when the chronology will be carried out simultaneously according to the Julian and Gregorian calendars for 13 days. In April 2008, the bill was voted down by a majority vote.

The material was prepared on the basis of information from RIA Novosti and open sources