Friesner, Esther M. Druid's Blood
Divergence: c 40 CE
What if: During the reign of Claudius in Rome, a druid magically isolated Britain from the rest of the world.
Summary: Mage-queen Victoria employs a Holmesian detective to find a stolen grimoire on which rests her authority.
Published: NAL/Signet 1988 (0451154088) and Headline 1989 (0747233128).