The problem with writing fact-based fiction is … well … facts. They can really mess up a good story.

I’d read that the Mortemarts, the family of Athénaïs, Madame de Montespan, lived on rue de Rosiers.

Perfect: rue des Rosiers is not far from where Claude des Oeillets, my main character, lived when she first came to Paris. It worked into the story perfectly. Their lives do become entwined; nobody knows how their relationship began, but as a novelist it helped that they were walking distance from one another.

Twice I scouted rue de Rosiers on research trips to Paris. I took many photos, but more than that: I walked the cobbles, dreaming.

Unfortunately, I didn’t read the fine print at the back of one of the texts. Hôtel Mortemart was on another rue de Rosiers, a street that is now named rue Saint-Guillaume … far, far from my heroine Claude.

And that’s not entirely certain, either. Some accounts claim that Hôtel Mortemart on rue Saint-Guillaume was built in 1663?three years after the young women meet.

So where were the Mortemarts living in 1660?

I’ve spent all morning researching possibilities (when I should have been writing). Vivonne, the eldest child, was born in the Tuileries palace. Both high-ranking parents served the King and Queen for three months of the year, and were likely entitled to live there … so that’s a possibility, although they certainly would have had a residence of their own in Paris.

I’m not really sure what I’m going to do about this. I could leave the setting as it is and make a note about the change in the Author’s Note or on my website.

Or I could change it, place the Mortemarts either in the Tuileries or on rue Saint-Guillaume …  difficult, and not necessarily good for the story.

I’m still perplexed.