 However , in 1642 civil war broke out between the rival Royalist supporters of King Charles I and Parliament . Raglan Castle was still held by Henry , then an elderly man , supported by his son , Lord Herbert . Both men were firm royalists . King Charles sent his own son , Prince Charles , on a fund @-@ raising tour of friendly regions , starting with Raglan Castle in October 1642 , following which Henry was promoted to be the first Marquess of Worcester . Tensions grew in the immediate region , partially driven by religious tensions between some of the more Protestant local people and the Roman Catholic Marquess ; on one of these occasions a local group attempted to search the castle , but were reportedly driven away by the sudden noise of Lord Herbert 's steam @-@ engine . The defences of Raglan were improved after this , with modern earthwork bastions built around the castle and a powder mill created ; a garrison of around 300 men was established at a cost of £ 40 @,@ 000 . Heavier cannon were installed in the bastions , with lighter pieces placed in the castle towers . 
