“Just picture it: the year is fifteen thirty-seven and Francis and Charles have decided that maybe, just maybe they should try and get along. So, offers are sent back and forth and a general plan starts to take form: The Duchy of Savoy will be given to one of Francis’s younger sons [1] who will be betrothed to Charles’s infant niece. [2]
Now this pleased absolutely no one, which is how you know it was a good deal. See, Francis wanted Savoy to be part of France, not just a friendly neighbor. And Charles didn’t want more land going to any of Francis’s ilk. But there they were.
At least until Prince Charles, Francis’s youngest son disappeared.”
Elopements Through History by Jonas Welsingham
[1] Initially, Charles suggested Prince Henri but, Francis still wasn’t happy with Henri due to an earlier elopement, so it was just left sort of nebulous.
[2] Charles didn’t have any legitimate daughters at this point
“The disappearance of King Francis’s favorite child was something of a damper on the peace talks. France began gearing up for war when news came that Emperor Charles was also missing a child: his widowed bastard daughter Margaret. It was then that Prince Charles’s note [1] was found by his father’s men and the Emperor found the priest that performed the marriage. [2]
While this served to stall actual fighting, it did ratchet up tension. It would be another year before an official peace was achieved.”
The Love Matches of the Children of Francis I by Nance Lawrence
[1] A simple note that stated he could not bear a betrothal to a child when he loved her elder cousin.
[2] What exactly was done to the priest isn’t known, but he was never heard from again.
“But even as posturing and demands resumed [1] the question remained: just where had the lovebirds gone?”
Elopements Through History by Jonas Welsingham
[1] Francis swung from demanding Prince Charles receive Savoy—after all he did marry the Emperor’s daughter—to refusing to acknowledge his youngest son. And Emperor Charles was just feeling contrary—why did his family have to get caught up in the Valois’s elopements?