In this article we are going to explain you the origin of the names of the week days in Spanish. The word semana (week) comes from septimana (seven days). The names of the days come from seven celestial objects that ancient Greeks saw moving in the sky.

The etymology of most of the week days has a big relation with Roman mythology. Romans saw at night a connection between their Gods and the sky that was changing according to the days, so they began to use as a natural way the names of their Gods for planets. Those that were possible to be followed by vision in the sky were: the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn. The Moon (Selena - Goddess of the moon, famous by its loves), Mars (Ares - God of the war, by the red like the blood), Mercury (Hermes - God of the traders, messenger of the Gods, and the nearest planet of sun), Jupiter (Zeus - God father, being the second most shining planet), Venus (Aphrodite - goddess of beauty and love, being the most shining planet), and Saturn (Cronos - God of time, being the slowest).

Under the Constantine empire and during great part of the Roman empire, it was named with some changes, the first day of the week doing reference to the Moon, followed by Mars, Mercury, Jupiter, Venus and Saturn.

In Spanish the planetary names remain in the five days of the week. These five days whose names finish in - es is an abbreviation of the Latin to say the word "día" dies, so that Monday or Lunes comes from the word moon and the planetary connection is also apparent in Tuesday or Martes (Mars), Wednesday Miércoles (Mercury), Thursday Jueves (Jupiter) and Friday Viernes (Venus).

Nevertheless, the words to designate to "Saturday" or Sábado and "Sunday"or Domingo , in Spanish were not adopted using the Roman model of denomination. Saturday comes from the word of Hebrew origin, that refers to the "Sabbat", the day of rest (in the Jewish and Christian tradition, God rested the seventh day of its creation).

And finally, Sunday Domingo has his origin in a Latin word, that means "the day of the God". It is not a coincidence that Sunday has a relation with the Sun and Jesus. Roman emperor Constantine adored Mitra (God of the Sun), but one day he had a dream in which he saw a cross in a sun with the inscription "win with this". It was in this way when he declared himself Christian and he dedicated Sunday like "the day of God".He also forbid to do manual works that day.

We can understand now the origin of the words that designate the days of the week in the Spanish language.