Who or what decided the length of a year and when a new one would start?

Answer by  tamarawilhite (17883)

The length of the year is based on the orbit of the Earth around the sun. When a new year starts varies across cultures and religions. For Christians, it starts January 1. For Muslims and Jews, it starts based on their lunar calendar.

Answer by  jreidmds (221)

Early civilizations quickly realized that events such as flooding of rivers, animal migration and time to plant crops occurred on a regular basis. By calibrating the height of the sun in the sky and the phases of the moon regular events could be tracked and calendars established.