Nerundill caught hints, snippets of conversation. The rumors surrounded a book, a book of magnificent power. A book that contained the knowledge of the ancients. With every new tantalizing bit of information he heard, his resolve to possess this book increased.
The ruling family depends on some magical artifact or place to secure their right to rule. A monarch isn't considered legitimate until he or she has been "accepted" by the artifact or place, whatever that might entail. It is also possible that some one else, not of the ruling family, could be accepted as the legitimate heir... A fact which the monarchs would like to keep secret.