Norman conquest of southern Italy Ofanto near Cannae, the site of Hannibal's victory over the Romans in 216 BC, and the Battle of Cannae was a decisive Byzantine victory; Amatus wrote that only ten Normans survived from a contingent of 250. After the battle, Ranulf Drengot (one of the Norman survivors) was elected leader of their company. Boioannes protected his gains by building a fortress at the Apennine pass, guarding the entrance to the Apulian plain. In 1019 Troia (as the fortress was known) was garrisoned by Boioannes' Norman troops, an indication of Norman willingness to fight on either side. With Norman mercenaries on both
Early Middle Ages had broken down, and the Roman army comprised mainly barbarians and soldiers recruited for a single campaign. The general decline in discipline also led to the use of smaller shields and lighter weaponry. Not wanting to share the glory, Eastern Emperor Valens ordered an attack on the Therving infantry under Fritigern without waiting for Western Emperor Gratian, who was on the way with reinforcements. While the Romans were fully engaged, the Greuthung cavalry arrived. Only one-third of the Roman army managed to escape. This represented the most shattering defeat that the Romans had suffered since the Battle of Cannae (216