The Aviators

This is an alternate history novel set in Europe in the fifth century. The Roman empire has split into three rival parts. The Eastern Empire, based in Constantinople, is the strongest. The Empire of Gaul is the weakest. Its only advantage is its aviators, who patrol the frontier and bring warning of any invasion.
Now Gaul has been invaded by the Huns. Rome''s generals must put aside their feuds and unite against this common enemy.
Magnus is an officer in the Empire of Gaul. He comes from a patrician family and cares nothing about the low-born aviators. But now Gaul''s best general has ordered Magnus to visit the aviators and persuade them to fly long, dangerous missions to scout out the enemy.
Incompetent Emperors are suspicious of their barbarian generals. Magnus becomes a pawn in these struggles and is struggling to navigate a way between these factions.
Lady Claudia, in Britain, has been forced into an arranged marriage with a powerful aristocrat. He is suspicious of the letters that Magnus is sending her from Italy. But then her husband''s bodyguard mutinies, and she is forced to make decisions that will affect all of Britain.