An Instance of the Fingerpost - Iain Pears

Set after the Restoration in the 1600s, this novel is made up of four different narratives, covering the same time period and a murder (or was it) at Oxford University. The first account is that of Marco da Cola, a Venetian visiting England. The next, by son of a possible traitor, Jack Prescott, builds on the first as does the third, that of cryptographer and mathematician (and priest) Dr Wallis. The final story, by historian Anthony Wood is intended to tie up loose ends and explain the preceding accounts. All the way through, you wonder who's telling the truth and what they have to gain by writing.
I have a slight issue with books that use real people in fictitious ways, as this one does, adding fictional characters to round out the plot. While it's well written, clearly the 17th Century has been well researched, I always feel using real people muddies the line between fictional and factual writing. The book contains a dramatis personae at the end to explain who's who, which makes it plain which parts of the story are pure fantasy and which aren't. It just doesn't sit well with me. Plenty of people have led truly fascinating lives and been involved in all manner of things, so write about them. You want to tell a story about a possible conspiracy that might affect the king, then make it up by all means. Adding real people to ground it in a time isn't necessary, plenty of historical fiction doesn't feel the need to do that. It just bothers me.
Anyway, as I say, this is well written and researched, cleverly constructed and while it dragged a little at times, a decent read.