Formerly a close friend and ally of the old High Priestess Carmina Curiana, Amelia inherited control of the Exalted Church when her old friend ascended to become a light spirit. During the uprising Amelia sided with Marius's faction of the Exalted Church but she has since repented those actions and is now seen as taking a fairly moderate view. Amelia tries to portray a more reasonable side of the Light, in the face of the various squabbling factions of the Exalted Church.
NB. There may well be other High Priest/Priestesses of the Light in the White City but Amelia is the official front of the Exalted Church.