Complex sentence: Her grandfather, a former nobleman who became a knight was one of the founders of the Independent Trade Cities during the Valbanill War which since then, the Cambell family have served as knights protecting the city's independence.
Split into simpler sentences: Her grandfather, a former nobleman who became a knight, was one of the founders of the Independent Trade Cities during the Valbanill War. After the war ended, the Cambell family served as knights protecting the city's independence.