Every society that practices the division of labor and levies taxes needs to keep track of time in a predictable manner, which usually implies time-keeping based on the movements of celestial bodies. Theoretically, the sun, the fixed stars, the planets, and the moon can be used for time-keeping purposes. Among these, the moon was used in the early stages of most cultures. In ancient Egypt a lunar or lunistellar calendar was in use, as evidenced by lunar festivals and names for the various stages of the moon.