Soult's cavalry under Jean Baptiste Marie Franceschi-Delonne overran la Romana's rear guard led by General Martinengo.

Mansilla de las Mulas is a town located 17 kilometres (11 mi) southeast of León, Spain.

La Romana's Spanish corps cooperated with Sir John Moore's British army in its advance into northern Spain and in its subsequent retreat to the northwest.

At Mansilla de las Mulas on the Esla River, the Spanish commander posted Martinengo's division to hold off Soult's pursuing French corps.

The next day, la Romana left León to the French along with hospitals crowded with 2,000 diseased or wounded Spanish soldiers.