Gildas' "De Excidio et Conquestu Britanniae" is the first surviving source to mention them, and he writes that during the Diocletian persecution, "God... kindled up among us bright luminaries of holy martyrs... Such were St. Alban of Verulam, Aaron and Julius, citizens of the city of legions and the rest, of both sexes, who in different places stood their ground in the Christian contest." Bede, drawing on Gildas, says in the "Ecclesiastical History of the English People" that in the same persecution during which Alban was martyred, so "suffered Aaron and Julius, citizens of Caerleon, and many others of both sexes throughout the land. After they had endured many horrible physical tortures, death brought an end to their struggles."