But history aside, this is a smart novel. There's scads of research here, into daily life in Enlightenment-era Saxony, German reactions to the French Revolution and Napoleon, early 19th-century German philosophy (by page two, a fellow Fichte devotee announces, ''there is no such concept as a thing in itself!''). Their three-year courtship parallels her losing battle with tuberculosis when she dies at 15, she is petrified as the vulnerable, ethereal and pure muse. Sophie is neither particularly pretty nor smart (her diary entries run to ''We began pickling the raspberries'' or ''Today no-one came and nothing happened''), but she is optimistic, innocent, malleable. After a strict Saxon upbringing and an education at Jena that revolved around Fichte's idealism, Hardenberg meets the 12-year-old Sophie and falls immediately in love. Fitzgerald presents a brilliant, subtly ironic portrayal of Friedrich von Hardenberg (aka Novalis) as an anti-Pygmalion who takes an unformed, all-too-human girl and fires her into an image of chaste muse.

In the introduction to his translation of Novalis's Henry von Ofterdingen, Palmer Hilty described Sophie von Kuhn as ''a callow, undistinguished girl of Thuringia.'' Not a terribly inspiring subject, unless the writer is Fitzgerald, the author of the 1979 Booker Prize winner Offshore and a shortlist perennial for the prize.

The blue flower by penelope fitzgerald