Fires Of The Faithful by Naomi Kritzer Book

For sixteen-year-old Eliana, life at her conservatory of music is a pleasant interlude between youth and adulthood, with the hope of a prestigious Imperial Court appointment at the end. But beyond the conservatory walls is a land blighted by war and inexplicable famine and dominated by a fearsome religious order known as the Fedeli, who are systematically stamping out all traces of the land's old beliefs. Soon not even the conservatory walls can hold out reality. When one classmate is brutally killed by the Fedeli for clinging to the forbuyden ways and another is kidnapped by the Circle--the mysterious and powerful mages who rule the land--Eliana can take no more. Especially not after she learns one of the Circle's most closely guarded secrets.