The Carthaginians suffered a wave of defections of local Celtiberian tribes to Rome. The Roman commanders captured Saguntum in 212BC and in 211BC hired 20,000 Celtiberian mercenaries to reinforce their army. Observing that the three Carthaginian armies were deployed apart from each other, the Romans split their forces. This strategy resulted in the Battle of Castulo and the Battle of Ilorca, usually combined as the Battle of the Upper Baetis. Both battles ended in complete defeat for the Romans, as Hasdrubal had bribed the Romans' mercenaries to desert. The Romans retreated to their coastal stronghold north of the Ebro, from which the Carthaginians again failed to expel them. Claudius Nero brought over reinforcements in 210BC and stabilised the situation.