<P> In 411, Jovinus rebelled and took over Constantine's remaining troops on the Rhine . He relied on the support of Burgundians and Alans to whom he offered supplies and land . In 413 Jovinus also recruited Sarus; Ataulf destroyed their regime in the name of Honorius and both Jovinus and Sarus were executed . The Burgundians were settled on the left bank of the Rhine . Ataulf then operated in the south of Gaul, sometimes with short - term supplies from the Romans . All usurpers had been defeated, but large barbarian groups remained un-subdued in both Gaul and Hispania. . The imperial government was quick to restore the Rhine frontier . The invading tribes of 407 had passed into Spain at the end of 409 but the Visigoths had exited Italy at the beginning of 412 and settled themselves in Narbo . </P> <P> Heraclianus was still in command in the diocese of Africa, the last of the clique that overthrew Stilicho to retain power . In 413 he led an invasion of Italy, lost to a subordinate of Constantius, and fled back to Africa where he was murdered by Constantius's agents . </P> <P> In January 414 Roman naval forces blockaded Ataulf in Narbo, where he married Galla Placidia . The choir at the wedding included Attalus, a puppet emperor without revenues or soldiers . Ataulf famously declared that he had abandoned his intention to set up a Gothic empire because of the irredeemable barbarity of his followers, and instead he sought to restore the Roman Empire . He handed Attalus over to Honorius's regime for mutilation, humiliation, and exile, and abandoned Attalus's supporters . (One of them, Paulinus Pellaeus, recorded that the Goths considered themselves merciful for allowing him and his household to leave destitute, but alive, without being raped .) Ataulf moved out of Gaul, to Barcelona . There his infant son by Galla Placidia was buried, and there Ataulf was assassinated by one of his household retainers, possibly a former follower of Sarus . His ultimate successor Wallia had no agreement with the Romans; his people had to plunder in Hispania for food . </P> <P> In 416 Wallia reached agreement with Constantius; he sent Galla Placidia back to Honorius and received provisions, six hundred thousand modii of wheat . From 416 to 418, Wallia's Goths campaigned in Hispania on Constantius's behalf, exterminating the Siling Vandals in Baetica and reducing the Alans to the point where the survivors sought the protection of the king of the Asding Vandals . (After retrenchment they formed another barbarian supergroup, but for the moment they were reduced in numbers and effectively cowed .) In 418, by agreement with Constantius, Wallia's Goths accepted land to farm in Aquitania . Constantius also reinstituted an annual council of the southern Gallic provinces, to meet at Arelate . Although Constantius rebuilt the western field army to some extent--the Notitia Dignitatum gives a list of the units of the western field army at this time--he did so only by replacing half of its units (vanished in the wars since 395) by re-graded barbarians, and by garrison troops removed from the frontier . </P>

What are three reasons the roman empire fell