The Shadow of Albion (Carolus Rex, Bk 1)

Thrust into a volatile world where King Henry IX rules over the English Empire, America never revolted, and Napoleon Bonaparte marches unchecked across Europe, is young Sarah Cunningham, ripped from our history by magic and the machinations of the dying Duchess of Roxbury.Magically coerced into believing she is Roxbury, Sarah finds herself caught up with the Duke of Wessex, the King's most trusted spy. A perilous adventure takes them into the black heart of Imperial France to rescue a missing princess before the last chance for peace dissolves and the world is left at the mercy of Napoleon....