Complex sentence: D. Peter sent a column to attack Valongo, which fell in an ambush by the Miguelists along the Ferreira Bridge, which made her go back to Rio Tinto, in a defeat that alarmed the city.
Split into simpler sentences: D. Peter sent a column to attack Valongo, which fell in an ambush by the Miguelists along the Ferreira Bridge. This made her go back to Rio Tinto in a defeat that alarmed the city.