This is an ALTERNATE HISTORY novel, set in the MIDDLE AGES. The empire of Charlemagne is falling apart. The emperor is a child, and ill. Europe is sliding into anarchy. ROME is threatened by PIRATES. In the west, the Empire of Gaul has found itself accidentally independent of the German emperor. The western empire, poorer and weaker than the East, has for centuries relied on the aviators of the courier service to patrol the frontier...