The French army advance along three roads. The main army of two corps use the centre road through the valley, One corps advance on either side along mountain roads.
The first battle of the campaign is fought on the western road through the mountains at the town of El Hoyo.
7th French corps is understrength because they have detached one of their four infantry brigades to garrison Abenojar. However Villatte is confident that he can defeat the Spanish.
General O'Donnell commands the 1st Spanish corps, which is the best of the four corps in the Spanish army. In addition he has the support of the garrison of El Hoyo.
The Spanish have 16000 infantry against 12000 French. Both have 1000 cavalry and 30 guns.
The full battle report can be found here
link