In Portuguese Monday is called Segunda-feira, Tuesday terca-feira, and so on with only Saturday and Sunday being Sabado and Domingo respectively. But in Spanish the days all have names: Lunes, Martes, Miercoles, etc.
Presumably a split occurred at some point but when was that?
Oooh, Oho i know this!
In the late 500's a bishop in what is now Braga started using numbers to name the days of the week in order to remove the pagan influence from them. The names themselves are derived from Ecclesiastic latin.
The bishops name was "Martinho de Dume", i can't find the exact council where the decision to make the change was made, but there was a council in 563 where that might have happened. It might have also happened in the councils of 561 or 572.
In any case, the first written reference that we can find of the "new" way of naming the week comes from this gravestone in Braga dated from 618.
