<P> After two years without a Western Emperor, the Eastern court nominated Anthemius, a successful general who had a strong claim on the Eastern throne . He arrived in Italy with an army, supported by Marcellinus and his fleet; he married his daughter to Ricimer, and he was proclaimed Augustus in 467 . In 468, at vast expense, the Eastern empire assembled an enormous force to help the West retake the Diocese of Africa . Marcellinus rapidly drove the Vandals from Sardinia and Sicily, and a land invasion evicted them from Tripolitania . The commander in chief with the main force defeated a Vandal fleet near Sicily and landed at Cape Bon . Here Genseric offered to surrender, if he could have a five - day truce to prepare the process . He used the respite to prepare a full - scale attack preceded by fireships, which destroyed most of the Roman fleet and killed many of its soldiers . The Vandals were confirmed in their possession of the Diocese of Africa and they retook Sardinia and Sicily . Marcellinus was murdered, possibly on orders from Ricimer . The Praetorian prefect of Gaul, Arvandus, tried to persuade the new king of the Visigoths to rebel, on the grounds that Roman power in Gaul was finished anyway, but he refused . </P> <P> Anthemius was still in command of an army in Italy . Additionally, in northern Gaul, a British army led by one Riothamus, operated in imperial interests . Anthemius sent his son over the Alps, with an army, to request that the Visigoths return southern Gaul to Roman control . This would have allowed the Empire land access to Hispania again . The Visigoths refused, defeated the forces of both Riothamus and Anthemius, and with the Burgundians took over almost all of the remaining imperial territory in southern Gaul . </P> <P> Ricimer then quarreled with Anthemius, and besieged him in Rome, which surrendered in July 472 after more months of starvation . Anthemius was captured and executed (on Ricimer's orders) by the Burgundian prince Gundobad . In August Ricimer died of a pulmonary haemorrhage . Olybrius, his new emperor, named Gundobad as his patrician, then died himself shortly thereafter . </P> <P> After the death of Olybrius there was a further interregnum until March 473, when Gundobad proclaimed Glycerius emperor . He may have made some attempt to intervene in Gaul; if so, it was unsuccessful . </P>

Which factor was most threatening to the cohesion of the roman empire