Portugal has a dictator: Salazar.
this is António de Oliveira Salazar (1889-1970)
and he wanted to control the country, so he created RTP.
"But why did the dictator wanted to create a TV channel to control Portugal?"
He was creating the television so the population could see on the TV what he wanted.
With that, at 4th September, 1956, a experimental presentation of the portuguese television is shown to the public.
But the regular emissions just started about 6 months later, at the 7th March, 1957.
RTP Starting their emissions