Karen Anderson & Poul Anderson 
Roma Mater 
King of Ys Book 1

Before there was an England, there was Roma Mater . . .Before King Arthur, there was the King of Ys . . .In the wild and eldritch time between the fall of Rome and the rise of our own age, the kingdom of Ys was ruled by the magic of The Nine and the might of the king, their husband. How the Nine conspired with their gods to bring him to them, though he belonged to Mithras and to Rome, is only the beginning of an enchanted saga that weaves together Celtic myth with distant memories of Roman Britain — and adds a magic of its own.