What are some of the problems or challenges of taking real characters from history and fictionalising them?
The biggest challenge is to wear the research lightly and not get sidetracked into slavish historical accuracy. I love peculiar facts, triggering images, but I’m not wedded to truth. As Michael Ondaatje says, “Facts breed, and what they produce is fiction.”

In Conceit, Pegge runs along Fleet Street past the Cock and Key, the Boar’s Head, the Star and Ram, and the Queen’s Head. All those taverns were on that street at that time. I didn’t want to kick readers out of the story by putting an alehouse on the wrong corner. Plausibility is needed to draw readers into the narrative. However, we aren’t on a tour of London. We only see the street Pegge’s on, how fast she’s moving, where she’s going. The lighter the research, the more fleet-footed the story.

Ivanhoe is an important historical novel, but it’s full of anachronism. You’d be foolish to read it as history. On the other hand, it’s dangerous for a writer to ignore the fact, especially if you’re in a dark stairwell, that some readers demand historical truth. In readings, there is often a moment—humorous if you’re in a plush seat, but awkward if you’re on stage—when a member of the audience takes a fictional event as the literal truth. Most writers waffle around trying to respond politely, but forthright writers insult the questioner by stating bluntly, “A novel is fiction. Not history. Not nonfiction. Not biography.” I suspect this is why book designers now put “a novel” under the title. Best to clear the air right from the start. It’s another way of warning readers, “anything goes.”

In my acknowledgements I say, “I have consulted the usual scholars and biographers but, after all is said and done, this is my 17th century and I have invented joyfully and freely. The characters entered fully into the spirit of it, contributing in surprising ways to their own fictionalization, John Donne most liberally of all. Perhaps this is fitting, for he confided to a friend, long after becoming a priest, ‘I did best when I had least truth for my subjects.’ ”