Little is known of Flavius Arbogastes other than his career as the Western Roman Empire's magister militum following the death of his predecessor, general Flavius Bauto 385. He aided Bauto in defeating the usurper Magnus Maximus and personally defeated Victor, the usurper's son. At Bauto's death, he was likely hailed as Bauto's replacement by the troops, and this was ratified by Theodosius I under the reign of Emperor Valentinian II in 388. Arbogast soon became the de facto ruler of the Western Roman Empire, and Valentinian II, age 20, had little say in any matters. Arbogast is personally credited as the mastermind of pagan senatorial uprising in Rome following the academic debates between Christian and pagan senators for generations regarding abandoning Christianity and returning to paganism. After his death his son Arigius succeeded in setting up a hereditary countship in Trier which lasted until Clovis. The county was largely supported by Franks. Arbogastes had an uncle and colleague called Richomeres and a nephew Theudemeres, who was king of the Franks.