Spanish horsemen worked as mercenaries first by Carthage and later by Rome. During the Second Punic War, riders from Celtiberia, Lusitania and Vettonia were used by Hannibal as heavy cavalry, in stark contrast to the more famed Numidian skirmishing cavalry. Livy compared them favorably against the Numidians, stating that Spanish riders were "their equals in speed and their superiors in strength and daring". Among them is mentioned a unit from the Celtiberian city of Uxama, whose riders wore helmets with jaws of beasts to scare their enemies away. Due to their performance at the battles of Trebia and Cannae, Livy would even state that Hispanic cavalry was superior to any other in the war. This eventually led the Roman military to ask for their own horsemen to the Celtiberian cities under their domain, using them to counter their Carthaginian homologues and exerting psychological warfare on them.