Medina de Rioseco
After the invasion, Díez organized a party of warriors composed of his friends and even members of his own family. At first, the conflict centered around the route between Madrid and Burgos. Later, he fought alongside the Spanish Army at the Cabezón de Pisuerga bridge in Valladolid and in Medina de Rioseco, Valladolid. The Spanish Army was routed in both of these battles.