Who named the days of the week?

Question

And how did they come into being?

Answer 1

No one can tell for sure, who exactly named the days of the week but based on where they came from (myths) I'm guessing they came from the people who created and evolved the stories.

The majority of the names of the week come from Scandinavian Myths, the Romans also couldn't resist having their say.

Here is a list of the names and the meanings/origin:
▼Sunday (Day of the Sun),
▼Monday (Day of the Moon),
▼Tuesday (Day of Tiu, one-handed God of War and Honor),
▼Wednesday (Day of Woden, King of the Gods),
▼Thursday (Day of Thor, God of Storms),
▼Friday (Day of Frigga, Goddess of Love),
▼Saturday (Day of Saturn, Romans Mythological God of God of sowing and blight).

Ofcourse other Myths and Religions also influenced it so to find the truest answer would indeed be difficult.

Answer 2

Here is a little different slant, though the information above is correct.

The calendar that the western civilization uses today is referred to as the Gregorian Calendar, adopted by Pope Gregory XIII and the Catholic church in 1582.

So, it could be said, having included the days of the week as they stood at the time, the pope did.