The celebration of the new year is the oldest of all holidays. It was first celebrated about 4000 years ago in ancient Babylon. Sometime around 2000 BC, the Babylonian New Year began with the first New Moon after the Vernal Equinox (the first day of spring).
The beginning of spring is a logical time to start a new year. It is the season of planting new crops, of blossoming plants, and rebirth. January 1st, on the other hand, has no astronomical nor agricultural significance. It is a purely arbitrary date.
The Babylonian new year celebration lasted for eleven days. Each day had its own particular way to celebrate, but it is safe to say that modern New Year's Eve festivities are boring in comparison.
The Romans continued to observe the new year in late March, but their calendar was continually changed by different emperors so that the calendar soon became out of synchronization with the sun.
In order to set the calendar right, the Roman senate declared January 1, 153 BC to be the beginning of the new year. But changes continued until Julius Caesar established what has come to be known as the Julian Calendar in 46 BC. It again established January 1 as the new year. But in order to synchronize the calendar with the sun, Caesar had to let the previous year go on and on for 445 days!