Complex sentence: William was the most notable member of the de Braose dynasty and his steady rise and sudden fall at the hands of King John is often taken as an example of that king's arbitrary and capricious behaviour towards his barons.
Split into simpler sentences: William was the most notable member of the de Braose dynasty. His steady rise and sudden fall at the hands of King John is often taken as an example of that king's arbitrary and capricious behaviour towards his barons.