During the Peninsular War, he assumed command over some 12,000 troops, defending the passes of Guadarrama, Fonfría, Navacerrada and Somosierra in the mountain range to the north of Madrid.
In the course of the Peninsular War, he commanded roughly 12,000 troops responsible for protecting the passes of Guadarrama, Fonfría, Navacerrada and Somosierra within the northern mountains adjacent to Madrid.