The Shattered Oath

From the back cover of the Baen first edition: "Uneasy lies the head that doesn't wear the crown - Ardagh Lithanial, Sidhe prince, is proud of his power and rank. Unfortunately, he is the younger brother of the ruler, Eirithan - and that ruler is paranoid about threats to his throne. even when none exist. Eirithan is all to willing to believe his brother guilty of treason. Swayed by political intriguers. he brands Ardagh an Oathbreaker, the foulest of criminals in Faerie. His honor falsely destroyed, Ardagh suffers the worst of all possible fates, banished to the land of the humans. Lost and alone in a world of threats from Christian kings and Viking raiders, Ardagh vows to cleanse his name. But first he must survive."