When I first started learning Spanish, I noticed that the days of the week seemed to be related to Roman or Greek gods, which were also planets. In English, our days of the week are named after Norse Gods, but many of them are analogous. For instance, Jueves in Spanish is for Jove/Jupiter, while Thursday is for Thor. Both of them own the thunderbolt, and are considered the HGIC in their respective faiths. It continued in French, and then, to my utter astonishment, in Japanese!
Monday=Lunes=Lundi=Getsuyobi=Moon Day. When I learned Italian, Lunedi was added to the mix.
Friday (Freyja day)=viernes=vendredi=kinyobi=venerdi=Venus day. Freyja is the Norse goddess of beauty, love, sexuality, etc. Just like Venus.
I asked my Japanese teacher why the days of the week were named after the same planets as they are in the Romance languages, and she just smiled and said, “because we know this too.” Before contact with the Western world, they used numbered days based on a lunar calendar. If I were a linguist, I would write my thesis on how the names of planets came to be associated with names of days in cultures that are linguistically unrelated.
Then I learned Portuguese. How very odd. They use numbers instead of planets/gods. Monday is segunda-feira (second day) Friday is sesta-feira (sixth day). The seventh day is Sabado (Sabbath, as in all Romance languages). When I told my Spanish speaking husband about this, he shook his head in disbelief. He can’t deal with the fact that Rio is pronounced HEE-yoo in Portuguese. The days of the week are just further examples to him of how backwards and incorrect the language must be. Some day I know he will study the language, and then it will all make sense.
I believe the Portuguese, and by extension, the Brazilians, are rebels. They do what they want, say what they want, and don’t need gods to tell them what day it is. It’s a good thing to think about on Mardi Gras/Carnival. This is their last burst of chaotic anarchy before they succumb to the Saturnine discipline of Lent.