Complex sentence: Then the legion moved to Caerleon and the civilians of the surrounding settlement took control and the place acquired the tribal suffix of'Dumnoniorum' when it was made the capital of the local Roman civitas.
Split into simpler sentences: Then the legion moved to Caerleon and the civilians of the surrounding settlement took control. The place acquired the tribal suffix of'Dumnoniorum' when it was made the capital of the local Roman civitas.