His family influence had made him a general at an age when he might reasonably have expected to lead a company, and he found himself by chance the interim commander of an army: hence came the astonishing series of blunders that led to the combat of Gamonal".
[2] Marching from Madrid, Belvedere had arrived at Burgos on 7 November, to strengthen its garrison of 1,600 men, and four guns, and the following day they were joined by the 2nd Division of the same army, with about 3,000 infantry and two regiments of hussars.
[note 1] At Gamonal, he lined up his troops against a far larger number of French units whose seven regiments of cavalry delivered a devastating charge at the Spanish infantry in the plain and the regiment of Spanish hussars covering their flank was "swept away like chaff before the wind"[2] and the attack was over before the Spaniards could form squares or even unlimber some of their cannon.
He was in an open plain, his right flank ill covered by the river Arlanzón, which was fordable in many places, his left completely 'in the air', near the village of Vellimar".
[2] Following the rout at Gamonal, Belvedere retreated to Lerma, and from there to Aranda de Duero before finally reaching Segovia, where the Junta Central relieved him of his command, appointing José Heredia y Velarde to take his place.