Complex sentence: The castle was held by Royalist forces for part of the English Civil War, but was surrendered to the Parliamentarians in 1644 following a short siege; its demolition was ordered soon after, and the castle was razed.
Split into simpler sentences: The castle was held by Royalist forces for part of the English Civil War, and was surrendered to the Parliamentarians in 1644 following a short siege. Its demolition was ordered soon after, and the castle was razed.