Ambrosius Aurelianus
The "Prophetiæ" is in some ways dependent on the "De Excidio et Conquestu Britanniæ" of Gildas. From Gildas and Nennius Geoffrey took the figure of Ambrosius Aurelianus, who figures in the preface to the prophecies (under a variant name): there is then a confusion made between Ambrosius and Merlin, deliberately done.