March equinox

[11] In astronomy, the March equinox is the zero point of sidereal time and, consequently, the right ascension and ecliptic longitude.

The Earth's axis causes the First Point of Aries to travel westwards across the sky at a rate of roughly one degree every 72 years.

[14] The Babylonian calendar began with the first new moon after the March equinox, the day after the return of the Sumerian goddess Inanna (later known as Ishtar) from the underworld, in the Akitu ceremony, with parades through the Ishtar Gate to the Eanna temple and the ritual re-enactment of the marriage to Tammuz, or Sumerian Dummuzi.

[citation needed] The Persian calendar begins each year at the northward equinox, observationally determined at Tehran.

The effect accumulated from inception in 45 BC until the 16th century, when the northern vernal equinox fell on 10 or 11 March.