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.