Shortly after France declared the war on Spain in May 1635, a French army under the Marshals of France Urbain de Maillé-Brézé and Gaspard III de Coligny, allied with the Dutch States Army, invaded the Spanish Netherlands from two sides and threatened Brussels before investing Leuven. The siege ended in a costly failure because of bad logistics and organization, and as the French army was decimated by the plague. The Cardinal-Infante Ferdinand, governor of the Spanish Netherlands, counterattacked and expelled the invaders, concentrating his resources against the Dutch over the following months. The recapture by the statholder Frederick Henry of Orange of the key fortress of Schenkenschans did not discouraged the Spanish, and the Count-Duke of Olivares continued determined to concentrate the war effort against the Dutch.