The Greeks named the
days week after the sun, the moon and the 5 known planets, which were in turn
named after the gods Ares, Hermes, Zeus, Aphrodite, and Cronus. The Greeks
called the days of the week the Theon hemerai "days of
the Gods". The Romans substituted their equivalent gods for the Greek
gods, Mars, Mercury, Jove (Jupiter), Venus, and Saturn. (The two pantheons are
very similar.) The Germanic peoples generally substituted roughly similar gods
for the Roman gods, Tiu (Twia), Woden, Thor, Freya (Fria), but did not
substitute Saturn.
Sunday -- Sun's day
Middle English sone(n)day or sun(nen)day
Old English sunnandæg "day of the sun"
Germanic sunnon-dagaz "day of the sun"
Latin dies solis "day of the sun"
Ancient Greek hemera heli(o)u, "day of the sun"
Old English sunnandæg "day of the sun"
Germanic sunnon-dagaz "day of the sun"
Latin dies solis "day of the sun"
Ancient Greek hemera heli(o)u, "day of the sun"
Monday -- Moon's day
Middle English monday or mone(n)day
Old English mon(an)dæg "day of the moon"
Latin dies lunae "day of the moon"
Ancient Greek hemera selenes "day of the moon"
Old English mon(an)dæg "day of the moon"
Latin dies lunae "day of the moon"
Ancient Greek hemera selenes "day of the moon"