Ancient civilizations believed that there were only seven planets in our Solar System, the Sun, Mercury, Venus, the Moon, Mars, Jupiter and Saturn. It was also widely believed that the movements of these planets had a profound effect on mankind's state of affairs. Many later astrology systems have since retained this ancient seven planet system.

The Ancients also believed that these seven planets each held a unique influence over its designated weekday. Sunday was influenced by Sol or the Sun, Monday by Luna or the Moon, Tuesday by Mars, Wednesday by Mercury, Thursday by Jupiter, Friday by Venus, and Saturday by Saturn. Alchemists from the middle Ages believed that there were seven metals which were matched with the seven planets. Gold with The Sun, Silver with The Moon, Copper with Venus, Iron with Mars, Tin with Jupiter, Lead with Saturn, and Quicksilver with Mercury. 

Early Astrologers detailed the respective planets positions among the stars at the time of a new birth, in order to determine that person’s fate. The general characteristics of a person were thought to be determined by which planet they were born under according to astrological calculations. Considered superstitious by some, astrological belief has been practiced since ancient times, and is still used every single day.