Fifty royal reads for royal wedding fans

At B&N Reads Tara Sonin tagged fifty royal reads for royal wedding fans. One entry on the list:
Reign of Madness, by Lynn Cullen

Isabel and Fernando are the heart of the Spanish monarchy…and Juana, their third child, will never sit on their throne. So when she marries, she hopes it may be everything to her that being Queen never would be. That is, until Juana unexpectedly winds up on the throne,