A Spanish army under the command of Don John of Austria, consisting of about 15,000 men, moved to raise the siege. It was divided in 2 corps, the Spanish Army of Flanders on the right and centre and the small corps of French rebels, of the Fronde, on the left under the command of Condé. The Spanish army included Spanish, German and Walloon troops, and a force of 2,000 English/Irish Royalists – formed as the nucleus of potential army for the invasion of England by Charles II, with Charles' brother James, Duke of York, amongst its commanders – was sent to relieve the town.