426/7 and 430 and the Franks along the Rhine in 428 and 432. Nevertheless, there were significant problems that threatened the viability of the Roman state in the west. The Visigoths were a constant presence in south-eastern Gaul and could not be dislodged. The Vandals in Hispania continued their incursions, and, in 429, they commenced their invasion of Mauretania Tingitana. The loss of these territories seriously impacted the state's ability to function. The burden of taxation became more and more intolerable as Rome's power decreased, and the loyalty of its remaining provinces was seriously impaired in consequence. In addition, the initial period of Valentinian's reign was dominated by the struggle among the leaders of the three principal army groups of the west – Flavius Felix, the senior magister militum praesentalis, Bonifacius, the magister militum per Africam and Flavius Aetius, the magister militum per Gallias. In 427, Felix accused Bonifacius of treason and demanded that he return to Italy. Bonifacius refused and defeated an army sent by Felix to capture him. Weakened, Felix was unable to resist Aetius who, with the support of Galla Placidia, replaced him as magister militum praesentalis in 429, before having him killed in 430. Bonifacius, in the meantime, had been unable to defeat Sigisvultus, whom Galla Placidia had sent to deal with the rebel. Bonifacius, therefore, entered into an agreement with the Vandals to come to his aid and, in return, they would divide the African provinces between themselves. Concerned by this turn of events and determined to hold onto the African provinces at all costs, the court at Ravenna sought reconciliation with Bonifacius, who agreed in 430 to affirm his allegiance to Valentinian III and stop the Vandal king Gaiseric. In 431, Bonifacius was crushed and fled to Italy, abandoning western North Africa. The imperial court, and especially Galla Placidia, worried about the power being wielded by Aetius, stripped him of his command and gave it to Bonifacius. In the civil war that followed, Bonifacius defeated Aetius at the Battle of Ravenna, but died of his wounds. Aetius fled to the Huns and, with their help, was able to persuade the court to reinstate him to his old position of magister militum praesentalis in 434. As a consequence, in 435, Valentinian was forced to conclude a peace with Gaiseric, whereby the Vandals kept all their possessions in North Africa in return for a payment of