New year is a tradition, but this holiday in the different countries at various times is celebrated. Moldova marks it at night since December, 31st for January, 1st. Already from the beginning of December all in expectation of a holiday. The history says, that the custom was born in Mesopotamia, in 3rd millenium B.C. Mesopotamia - the earth between the rivers, between the Tiger and Euphrates. Now as Mesopotamia understand basically a valley in the bottom current of these rivers, and add to it the earths to the east from the Tiger and to the West from Euphrates. Now it is area of modern Iraq.
12 days people suit a carnival, a masquerade, various processions. The holiday is devoted the beginnings of agricultural works. During a holiday it was forbidden to work and manage courts.
Gradually custom to celebrate New year became tradition in other countries - at first were in Babylon to the captivity иудеи, from them Greeks and further to the Western Europe.
When July Caesar has entered a new calendar (now it name Juliansky), began to consider the first day of January in the first afternoon of new year. Romans this day made a sacrifice to two-faced god Janus and began this day large actions, including the first day of year favorable for any undertakings.
The tradition to mark Old New year goes from a divergence юлианского a calendar (or otherwise a calendar of "old style») and a Gregorian calendar - on what now there lives all world. The divergence of calendars makes 13 days. Old New year is a rare historical phenomenon, an additional holiday which has turned out as a result of chronology change. Because of the given divergence of calendars we mark two «New year» - on old and new style. Thus, at night with 13 for January, 14th everyone presumes to itself(himself) «допраздновать» the most favourite holiday. After all for many believing people Old New year has special value as with all the heart celebrate it they can only after the termination of the Christmas post.
Our inquiry: the difference between юлианским and Gregorian calendars increases every century when the number of hundreds in a year A.D. is not multiple to four, for one day. Therefore since March, 1st, 2100 this difference will make 14 days. And since 2101 the Christmas and Old New year will be marked one day later.