WESTMARK 02: Der Turmfalke

Blurb

The Kestrel is a fantasy novel by Lloyd Alexander, the second of three books often called the Westmark trilogy. The novel won the Parent's Choice Award in fiction for Fall 1982.
It is set in Westmark, "an imaginary kingdom with a post-Napoleonic cast". Another reviewer has called the series "historical fantasy, set in a time much like our 18th century".