Underlying much of the whole King of Ys series is the subject of the public welfare. The novels discuss in detail the efforts of Gratillonius and others to make a better world for people to live in; much of the discussion focuses on the city of Ys and the effort of Gratillonius and the Nine to make it a prosperous and happy place. The Roman Empire is disintegrating, although no one at the time knows it.

The Scoti ravage Roman Britain, while Saxons and Jutes sail along the coast of Gaul, murdering and pillaging as they go.

The Franks have settled down in much of Gaul, and they continue their custom of brutal human sacrifices to their gods. The Empire endures one civil war after another and is consequently so weakened that it has to make concessions to the barbarians that raid across its borders.

When...