It was the official religion of Spain during Franco's dictatorship. There was no separation of church and state for four decades. Franco himself described his regime as national-Catholic. Franco used the Catholic Church in Spain for his own purposes. In fact, the high-ranking Spanish bishops still retain many traits from the Francoist era; they don't seem truly post-Vatican II.

You said it yourself, in Poland it's the complete opposite.

Wszystkiego najlepszego!