For other uses see Aegidius (disambiguation).
Aegidius (unknown - 464 or 465) was a Gallo-Roman promoted as magister militum in Gaul under Aëtius around 450. He was an ardent supporter of Majorian, whom he helped to gain power. When Majorian lost ground against Ricimer in the chaos of Gaul in the middle of the fifth century he rebelled and created a Roman rump state that became to be known as the Domain of Soissons.
Aegidius allied himself with Childeric I, Merovingian king of the Salian Franks of Tournai. According to Gregory of Tours, Aegidius even succeeded the banished Childeric in the latter's kingdom for a while, but Childeric would later return.
The death of Aegidius occurred under unclear circumstances at the Loire in 464 or 465, either by poison or in ambush. He was succeeded first by the Comes Paulus, who was killed shortly afterwards by Childeric, and then by his son Syagrius.
There is a tradition, dating from Gildas, that the Britons, having been deprived of Roman military protection after 410, wrote to a "Roman commander Agitus, thrice consul", who may be Aegidius, or, more probably, Aëtius.