 Complete the following phrase:  When Carthaginian commander Hannibal Barca fought the Romans, he recruited several Gaulish mercenaries who fought on his side at Cannae. It was this Gaulish participation that caused Provence to be annexed in 122 BC by the Roman Republic. Later, the Consul of Gaul  Julius Caesar  conquered all of Gaul. Despite Gaulish opposition led by Vercingetorix, the Gauls succumbed to the Roman onslaught. The Gauls had some success at first at 