Nowruz with Pahlavi's family

When was Nowruz first celebrated?

Described by 11th-century Persian astronomer and poet Omar Khayyam as “the renewal of the world”, Nowruz dates back thousands of years. It is not known exactly how far back Nowruz goes, but current estimates are that it is at least 3,000 years old, when the Persian empire extended beyond the borders of modern Iran. It is not mentioned in the Avesta.