The Babylonians are commonly credited with the earliest recorded New Year's celebrations.
Babylonian New Year observances were connected with Akitu, an important Mesopotamian festival documented in ancient sources. The festival took place in spring, around the time of the first new moon after the spring equinox, rather than on January 1.
Akitu lasted several days and combined religious ceremonies, processions, royal rituals, and the reaffirmation of political and cosmic order. It honored major Mesopotamian deities, especially Marduk in Babylonian practice. The exact form of the festival changed over long periods and between cities.
This fact is often misunderstood as meaning the Babylonians invented the modern January 1 holiday. They did not. January 1 became the beginning of the Roman civil year through later calendar developments, while many ancient cultures used spring or autumn dates for their new year.