If you are interested in this historical period, the Great Anarchy, you should read the Cadfael Chronicles by Ellis Peters. Her 20 volumes are mysteries set against the war between Maud and Stephen, but Peters' work is much more intelligent, and well-written.
One can suspect that Ken Follett benefited from Peters' meticulous research of the period. But his book is history sensationalized for the mass market.
I don't think I'll manage to read "Pillars of the Earth" all the way through.