Complex sentence: Victory seemed a matter of time, and in Madrid, it was confidently expected that the fall of Oporto was imminent, but suddenly the invaders were confronted with a national rebellion, which spread around the Provinces of Trás-os-Montes and Minho.
Split into simpler sentences: Victory seemed a question of time, and in Madrid, it was confidently expected that the fall of Oporto was imminent. But suddenly the invaders were confronted with a national rebellion, which spread around the Provinces of Trás-os-Montes and Minho.