Why are there 7 days in a week?

While the movement of Earth and Sun give us natural concepts like days and years and the Moon’s phases give us the month, there is no such natural reason for a seven-day week.

The ancient Babylonian’s  are likely responsible for the concept of a seven day week.  The number seven had a mystical significance to Babylonians. It was associated with the seven heavenly bodies; the Sun, Moon, Mars, Mercury, Jupiter, Venus and Saturn.  For this reason, some believe, marking rituals every seventh-day became important.

How the days of the week got their name

The popularity of the seven-day week – and its prominence in modern calendars – can be traced to its adoption by the Romans.  They named the days of the week after the pagan gods of Rome, the Sun and the Moon.

How the days of the week got their name.
How the days of the week got their name.

MONDAY

Originates from the Old English “Monandaeg” (day of the Moon) and is the translation of the Latin name, “dies Lunae”.

TUESDAY

Derived from the Old English “Tyr’s day”.  Tyr was the Nordic god of single combat and heroic glory in Norse mythology.  The name is based on Latied “dies Martis” (day of Mars).  Mars was the Roman god of war.

WEDNESDAY

From the Old English “day of Woden”.  Wodin, or Odin, was a powerful Norse god and a prominent god of the Anglo-Saxons in England.  It is based on Latin “dies Mercurii” (day of Mercury).  The Greek name was Hermes, who was the patron god of financial gain, commerce, eloquence, communication, travelers, boundaries, luck, trickery, and thieves.

THURSDAY

Originates from Old English, the day of Punor (Thor).  Thor was the Germanic and Norse god of thunder.  It is based on the Latin “dies Iovis” (day of Jupiter). The Greek name for this is Zeus, who was also king of the gods and the god of sky and thunder.

FRIDAY

Originates from the Old English Frigedaeg (day of Frige).  Frige was the Germanic goddess of beauty, who is a later incarnation of the Norse goddess Frig, but also connected to the goddess Freyja.  It is based on the Latin “dies Veneris (Day of Venus).  The Greek name is Aphrodite.  Venus was the Roman god of beauty, love, and sex.  The term “TGIF” actually means, “Thank God It’s Frigedaeg“*.

SATURDAY

Named after the Roman god, Saturn (day of Saturn).  The Greek name for this is Cronus or Kronos.  According to Roman mythology, he was the first god of the Capital, known historically as Saturnius Mons, and was seen as a god of generation, dissolution, plenty, wealth, agriculture, periodical renewal, and liberation.  In Greek mythology, he was the leader and youngest of the first generation of Titans, divine descendants of Gaia, the Earth, and Uranus, the sky.  He overthrew his father and ruled during the mythological Golden Age, until he was overthrown by his own son, Zeus, and imprisoned in Tartanus.

SUNDAY

Comes from the Old English “Sunnandaeg” (day of the Sun).  This is the translation of the Late phrase “dies solis”.

 

* Not really

Source
http://www.bbc.co.uk/religion/0/20394641