The deeds (though probably not the names) of Faganus and Dinaw - as Duvianus - were the creations of Geoffrey of Monmouth, Historia regum Britanniae Book IV c.19, whereas Aaron (along with Julius) is attested as a Romano-British martyr at Caerleon by Gildas, De excidio Britonum c.10, followed by Bede, Historia ecclesiastica Book I c.7, and many later writers.