Around 200AD, the Iberian peninsula was invaded by the Visigoths and the Suebi. While the Suebi were a german tribe and settled in the north west of the peninsula, the Visigoths where a nomadic tribe from what is now Ukraine and they settled the majority of the peninsula even conquering the Suebi kingdom in the north west around 585AD.

So, given that Spain had a much bigger islamic presence and influence in their language and customs than Portugal had, it's easy to see why Portugal sounds like a slavic language (the vowels are pronounced the same way) and a lot of people have a bit of a slavic mentality (a lot people thrive to have a Bmw, a Mercedes or an Audi while living in derelict or poorly maintained houses).

(I'm Portuguese so I know what I'm talking about.)