The ancient Babylonian festival often identified as the earliest recorded New Year celebration is Akitu.
Akitu was a major Mesopotamian festival associated with the beginning of the agricultural year. In Babylon, it was held in the month of Nisanu, corresponding roughly to March or April in the modern calendar. The festival honored the god Marduk and included processions, rituals, and royal ceremonies.
The celebration lasted several days and played a political as well as religious role. A central ritual presented the king before Marduk, linking the ruler's authority with the restoration of cosmic order for the coming year.
Calling Akitu the “first” New Year celebration needs care. Surviving evidence makes it one of the earliest documented examples, not proof that no earlier seasonal observance existed. Its date also differs from January 1 because Babylonian calendars were lunisolar and tied the festival to spring.