Complex sentence: He constructed an estimated 100 castles and abbeys across the Loire Valley in what is now France, fought successive wars with neighbors in Brittany, Blois, Poitou and Aquitaine and traveled four times to Jerusalem on pilgrimage during the course of his life.
Split into simpler sentences: He constructed an estimated 100 of them, along with abbeys, across the Loire Valley in what is now France. He fought successive wars with neighbors in Brittany, Blois, Poitou and Aquitaine and traveled four times to Jerusalem on pilgrimage during the course of his life.