Calendar from Lat. calendarium, literally – a debt book (debtors paid interest on the 1st day of each month – a system for counting long periods of time, using the periodicity of natural phenomena, manifested especially clearly in the movements of the celestial bodies. The development of calendars reflects the conditions of the economic structure of peoples. Based on rich ethnographic material one can trace how identical forms of economic structure lead to the formation of similar calendar concepts. All nationalities have the concept of the year; the year is divided into seasons, the number of which is most often four, but can reach up to seven. Seasons are divided into smaller intervals (from 10 to 12 per year), having a connection with the lunar months. “The names of the months reflect the economic basis of life, for example, among the Siberian Evenki reindeer herders there is a month “when the deer peels the skin from the horns”, the month of “calving” and etc.; among the Tungus from the banks of the Amur there is a month of “arrival of chum salmon”, a month of “spawning.” Observations of luminaries have an undoubted connection with the calculation of time; The Nanais have a month “when the Bear’s head sets before dawn.” In tropical countries, a double cycle of field work (2 sowings and 2 harvests) coincides with a certain position in the sky of the constellation Orion; in other countries the Pleiades play an equally important role" (Great Soviet Encyclopedia, edited by B. A. Vvedensky, Moscow, 1953, vol. 19, p. 402). The first recorded physical calendars, dependent on the development of writing in the Ancient Near East, are the Bronze Age Egyptian and Sumerian calendars. The Ancient Egyptian calendar, associated with the visible annual movement of the Sun, is the prototype of all solar calendars. It was created back in the 4th millennium BC. e. for the purpose of regulating field work. It is known that around 2800 BC. e. the basic unit of time was the year; it was divided into 3 seasons (flood, winter and sowing, harvest) of 4 months each. The month was divided into 3 decades, that is, it had 30 days. After 12 months, 5 additional days were inserted into the calendar. Thus, all years had the same length of 365 days. The beginning of the calendar year was recorded on the day of the first visible (or heliacal, occurring against the background of dawn) rising of Sirius (Canis Major).
The ancient Indo-Europeans, who originated as a linguistic group in the Southern Urals, had ideas about the calendar. During the Vedic period, the ancient Indo-European Indians developed sophisticated timekeeping methodology and calendars for Vedic rituals. For example, the Vedanga calendar in ancient India was based on astronomical research from the Vedic period and was not borrowed from other cultures.
A large number of calendar systems in the Ancient Near East were based on the Babylonian calendar dating from the Iron Age, among them the calendar system of the Persian Empire, which dates back to the Indo-European culture, which in turn gave rise to the Zoroastrian calendar. The Babylonian New Year began with the first new moon after the northern equinox. The ancient celebrations lasted 11 days.
The basis of ancient Greek chronology was the counting of time according to the Olympiads – national festivals and games that took place once every 4 years in Olympia. The era of the Olympics is taken to be the summer of 776 BC; According to legend, the first Olympics took place this year.
In ancient times, calendars were lunisolar, depending on the introduction of intermediate months to align the solar and lunar years. This was largely observational, but there may have been early attempts to algorithmically model intercalation structure, as evidenced by the fragmentary 2nd century Coligny calendar. Depending on the calendar used, new years are often classified as lunar new years, lunisolar new years, or solar new years.
The Roman calendar was reformed by Julius Caesar in 46 BC. His "Julian" calendar no longer depended on the observation of the new moon, but followed the algorithm of introducing a leap day every four years. This led to the separation of the calendar month from the lunar period.
According to the ancient Roman calendar, the year consisted of 10 months, with March being considered the first month, in honor of the god Mars. At the turn of the 7th and 6th centuries. BC e. A calendar was borrowed from the Etruscans, in which the year was divided into 12 months: January and February followed December. The months of the Roman calendar had the following names:
mensis – month
Martius – March (in honor of the god Mars)
Aprilis – April (warmed by the Sun)
Maius – May (named after the goddess Maya)
Junius – June (named after the goddess Juno).
Quintflis – fifth (from 44 BC. Julius – July, in honor of Julius Caesar)
Sextllis – sixth (from 8 AD Augustus – August, in honor of the Roman emperor Augustus)
September – September (seventh)