What should I include in my story?

When writing historical fiction, writers face a unique dilemma.  In my last post I wrote about a book I recently read and greatly enjoyed - The Physician.  It is historical fiction, and one of the aspects I liked best about the book is the setting, and learning about a time in the distant past - what people ate, what they wore, how they celebrated.  As in any work of historical fiction, the details are fictional.  But in any good historical novel, the details are based in research.

Historical novelists must often do extensive research before they write.  Several years ago, when I first began my own historical novel, I had just finished reading A Respectable Trade, by Philippa Gregory.  It did for me what great books do - it made me laugh, cry and care.  I was so moved that I wrote to Ms. Gregory, and told her how the book impacted me, and also asked her questions about how she did her research and what the writing process is like for a writer of historical fiction.  This wonderful writer, who has sold millions of copies of her books, actually wrote back to me!  She offered very helpful advice.  She spends anywhere from 6 months to a year or two conducting research.  Then she writes. 

I do my first draft in long hand.

In preparation for writing my own historical novel, I read dozens of books and researched the settings and the time periods, and the key figures, before I wrote a word.  Then I began to write, but I continued to do research as I wrote.  I also visited plantations in South Carolina and sites in England where Joanna Vassa lived, and her burial site.  This research was invaluable.  But here's the problem.  I learned so many fascinating facts, I wanted to include them all.  But then it would not be a novel, but a compilation of research.  So what should historical novelists include?  I believe we should include only those facts and details that are necessary to the storyline.  That's not always easy to decipher, so I think during the editing phase, if there are extraneous details that don't add to the story, or are actually necessary to the story, they should be expunged!  That's the painful work of writing, killing off some of our sentences, and even paragraphs and pages, that don't contribute to the story.  Ouch!