Dagalaifus was a Roman army officer of Germanic descent. A pagan, he served as consul in 366. In the year 361, he was appointed by Emperor Julian as '' comes domesticorum'' (Commander of the Household Guard). He accompanied Julian on his march through Illyricum to quell what remained of the government of Constantius II that year. He led a party into Sirmium that arrested the commander of the resisting army, Lucillianus. In the spring of 363, Dagalaifus was part of Julian's ultimately-disastrous invasion of Persia. On June 26, while still campaigning, Julian was killed in a skirmish. Dagalaifus, who had been with the rear guard, played an important role in the election of the next emperor. The council of military officers (including Dagalaifus) finally agreed on the new ''comes domesticorum'',

Jovian Jovian is the adjectival form of Jupiter and may refer to: * Jovian (emperor) (Flavius Iovianus Augustus), Roman emperor (363–364 AD) * Jovians and Herculians, Roman imperial guard corps * Jovian (lemur), a Coquerel's sifaka known for ''Zoboomafo ...

, to succeed Julian. Jovian was a Christian whose father Varronianus had himself once served as ''comes domesticorum''. As emperor, Jovian quickly arranged an end to the Persian hostilities on terms that were far from advantageous to Rome. He appointed Dagalaifus ''

magister equitum The , in English Master of the Horse or Master of the Cavalry, was a Roman magistrate appointed as lieutenant to a dictator. His nominal function was to serve as commander of the Roman cavalry in time of war, but just as a dictator could be nomi ...

'' (commander of the cavalry), where Dagalaifus presumably succeeded the then-restored Lucillianus to that position. Following the death of Jovian after only several months’ rule, Dagalaifus was again influential in the election of Valentinian as the next Roman Emperor. Although he opposed Valentinian's decision to elevate his brother, Valens, as co-emperor, Dagalaifus was retained and presumably continued ''magister equitum'' serving under Valentinian in the

Western Empire The Western Roman Empire comprised the western provinces of the Roman Empire at any time during which they were administered by a separate independent Imperial court; in particular, this term is used in historiography to describe the period fr ...

. In the winter of late 365, Valentinian learned that the

Alemanni The Alemanni or Alamanni, were a confederation of Germanic tribes * * * on the Upper Rhine River. First mentioned by Cassius Dio in the context of the campaign of Caracalla of 213, the Alemanni captured the in 260, and later expanded into pres ...

had crossed the Rhine and defeated his armies in eastern Gaul around

Moguntiacum Mainz () is the capital and largest city of Rhineland-Palatinate, Germany. Mainz is on the left bank of the Rhine, opposite to the place that the Main joins the Rhine. Downstream of the confluence, the Rhine flows to the north-west, with Mainz ...

( Mainz). This was the beginning of the long Alemannic War that would dominate Valentinian's reign. The emperor initially dispatched Dagalaifus to defeat the invaders. But by the time he arrived, he found the Alemannic forces too scattered to pursue. He was then recalled and replaced with the ''Magister Equitum'', Jovinus. As reward for his support in elevating Valentinian to the imperial purple in 364, Dagalaifus was appointed by him to the consulship for 366.Ammianus Marcellinus, Res Gestae XXVII.2.1 He served as consul alongside the emperor's seven-year-old son, Gratian. Dagalaifus does not appear again in the available historical records.

References

{{DISPLAYTITLE:Dagalaifus (''magister equitum'') 4th-century Germanic people 4th-century Romans 4th-century Roman consuls Comites domesticorum Germanic warriors Imperial Roman consuls Magistri equitum (Roman Empire)