How do you pronounce it? We have an ongoing debate in our house - one camp says it should be mat-ee-uss wheras the other camps says it should be ma-tyoo-ss.
There are some superb ros� wines available but Mateus definitely isn't one of them. Worse still, Mateus was responsible for the decline in sales of some really great ros�s. (People tried Mateus and thought that all ros�s would taste like it).
However, to answer your question:
Back in the days when Mateus was widely advertised on TV, it was always pronounced 'mat -ay-us' (with the stress on the second syllable).
This was my first (and a lot of others as well) wine back in 1960 something and we really thought it was the height of sophistication. I remember drinking with a meal at a Chinese restaurant. How daring!