Hamilton, Franklin. "What If—?"
Divergence: 1066 CE
What if: William the Conqueror was beaten at Hastings and the Norman Conquest was averted.
Summary: Two possibilities; either fragmented England was later occupied by France or Harold united the land, but it spent the next millenium in isolation.
Comments: Franklin Hamilton is a pseudonym for Robert Silverberg.
Published: In 1066, Dial 1964.