I was referring to Goddess' book, not to Pillars or Shogun.
I knew that both of them (Pillars and Shogun) were based on real events, the Anarchy period (death of King Henry w/o a solid heir) and the warring daimyo period in Japan (one of many such eras in Japan). Toranaga is actually based on Tokugawa who became Shogun.
Pillars really paints a good picture of 12th century England, especially involving the Church.
My all-time favorite historical fiction novel is actually "The First Man in Rome" by Colleen McCullough. Chronicles the rise of Marius & Sulla toward the end of the republic phase of Rome. (Maybe I mentioned this book before, I don't remember. Please forgive my sieve-like memory.)