Hilary Mantel said this quote
“ I make up as little as possible. I spend a great deal of time on research, on finding all the available accounts of a scene or incident, finding out all the background details and the biographies of the people involved there, and I try to run up all the accounts side by side to see where the contradictions are and to look where things have gone missing. And it's really in the gap - it's in the erasures - that I think the novelist can best go to work because inevitably in history in any period, we know a lot about what happened, but we may be far hazier on why it happened. And there's always the question, why did it happen the way it did? Where was the turning point? ”