Explanation of the ordering of the names of the days of the week after the heavenly bodies, in Latin and derived languages. Around the circle the bodies are ordered, from Saturn, in ascending order of speed of movement around the zodiac. Each body was supposed to have supremacy for an hour at a time, in this same order. Thus if Saturn ruled the first hour of the first day, the Sun would rule that of the second (after 3 complete cycles and 3 hours over, linked by the arrowed line), the moon the third, and so forth, and these first-hour rulers gave their names to the days themselves.