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)