Battle of Cape Bon ( 468 ) The Battle of Cape Bon was an engagement during a joint military expedition of the Western and Eastern Roman Empire s led by Basiliscus against the Vandal capital of Carthage in 468 . The invasion of the kingdom of the Vandals was one of the greatest military undertakings recorded in the annals of history , a combined amphibious operation with over ten thousand ships and one hundred thousand soldiers . The purpose of the operation was to punish the Vandal king Gaiseric for the sacking of Rome in 455 , in which the former capital of the Western Roman Empire had been overwhelmed , and the Empress Licinia Eudoxia ( widow of Emperor Valentinian III ) and her daughters had been taken as hostages . Background . The plan was concerted between Eastern Emperor Leo , Western Emperor Anthemius , and General Marcellinus , who enjoyed independence in Illyricum . Basiliscus was ordered to sail directly to Carthage , while Marcellinus attacked and took Sardinia , and a third army , commanded by Heraclius of Edessa , landed on the Libyan coast east of Carthage , making rapid progress . It appears that the combined forces met in Sicily , whence the three fleets moved at different periods . Procopius records that Basiliscus , brother - in - law to Emperor Leo , had been selected as general by the emperor in hope he would balance the growing influence of the Alan " Magister militum " Aspar who sought to control Leo ; however , Basiliscus sought the friendship of Aspar to further his own designs on the throne , and Aspar " repeatedly urged upon Basiliscus that he should spare the Vandals and Genseric " . Ancient and modern historians provided different estimates for the number of ships and troops commanded by Basiliscus , as well as for the expenses of the expedition , although both were enormous sums . According to the text of Priscus , 100 , 000 ships were assembled , although modern scholars have emended this to 1100 , which is closer to Cedrenus ' s figure of 1113 vessels . The figures for the money spent this expedition ranges from the 1300 " centaria " of gold reported by Priscus and Procopius ( 130 , 000 Roman pounds ) , to the 64 , 000 pounds of gold and 700 , 000 pounds of silver by John Lydus and to 65 , 000 of gold and 700 , 000 of silver by Candidus . Battle . Sardinia and Libya were already conquered by Marcellinus and Heraclius , when Basiliscus cast anchor off the " Promontorium Mercurii " , now Cap Bon , opposite Sicily , about forty miles from Carthage . Geiseric requested Basiliscus to allow him five days to draw up the conditions of a peace . During the negotiations , Geiseric gathered his ships and suddenly attacked the Roman fleet . The Vandals had filled many vessels with combustible materials . During the night , these fire ship s were propelled against the unguarded and unsuspecting Roman fleet . The Byzantine commanders tried to rescue some ships from destruction , but these manoeuvres were blocked by the attack of other Vandal vessels . Basiliscus fled in the heat of the battle . One act of heroism stands forth from this naval defeat . Despite the situation , Basiliscus ' lieutenant , Joannes , bravely fought the Vandal onslaught ; Procopius describes him as " standing on the deck " and turning from side to side kept killing very great numbers of the enemy " . Upon seeing that his ship was about to be captured , he refused to surrender to Genso , the son of Gaiseric , instead leaped overboard in heavy armor and drowned himself . His last words were that he " would never come under the hands of dogs " . Aftermath . One half of the Roman fleet was burned , sunk , or captured , and the other half followed the fugitive Basiliscus . The whole expedition had failed . Heraclius effected his retreat through the desert into Tripolitania , holding the position for two years until recalled ; Marcellinus retired to Sicily , where he was reached by Basiliscus ; the general was , however , assassinated , perhaps at the instigation of Ricimer , by one of his own captains ; and the king of the Vandals expressed his surprise and satisfaction , that the Romans themselves would remove from the world his most formidable antagonists . After returning to Constantinople , Basiliscus hid in the church of Hagia Sophia to escape the wrath of the people and the revenge of the Emperor . By the mediation of Verina , Basiliscus obtained the Imperial pardon , and was punished merely with banishment to Heraclea Sintica , in Thrace .