GIVE ANSWERS - Ἑλληνική

Ιn ancient Greece the New Year was not celebrated, since for that time the beginning of each month, called ”noumenia”, was more important. In ancient Greece the year consisted of twelve lunar months, usually alternating between 29 and 30 days. The boundaries of each month were marked by the appearance of two new moons so that its duration was about 29 ½ days. Problematic, however, was the introduction of a year of 354 days, which without action would steadily increase, since a solar year has 365 days. To eliminate this difference, a month of about 22-23 days was added at intervals, usually every two years. Most probably the Greeks in the 8th century B.C. used a calendar year of about 12 months since a mention of its existence is found in Hesiod, though some question the value of this evidence.
It was not until Roman times, and under the influence of Rome, that the New Year’s ceremony began to extend to the whole of Roman Empire and thus to Greece. It was Julius Caesar, in 46 B.C., who fixed January 1 as the beginning of the year, which has since prevailed in the West with few and local and temporary exceptions, such as in the time of Charlemagne (the latter, because he happened to ascend the throne at Christmas 800 AD fixed December 25 as the beginning of the year for his reign). To Julius Caesar and to the knowledge of the famous astronomer from Alexandria, Sosigenes, whose help he had asked for, we owe the adjustment of the year during the rotation of the earth around the sun. The order of the months, their duration and their names, which is valid today, we owe largely to the Roman general and politician.