If you like, as I do, SJ Parris’ historical mystery series featuring real-life monk/philosopher/astronomer Giordano Bruno, you might be interested in the non-fiction book, The Pope & the Heretic: The True Story of Giordano Bruno, the Man Who Dared to Defy the Roman Inquisition, by Michael White. Even though the title is too long. I’ve had this on eReaderIQ for a little while, and it has just now dropped to $2.99 in the US, and it’s discountable at Kobo US.
I like it a lot when authors use real people in their historical mysteries, and like it even more when there is an Author’s Note that clarifies what/who is historical, and what/who is made up. And The Pope & the Heretic seems as if it will be basically a book-length Author’s Note!