Reading over several Tudor timelines the other day, a question popped into the mind: What would happen in a world with Mary Stuart married to a healthier, fertile Francis II? One where the Tudors proved no more prosperous than IOTL?
Francis's father Henry II had six (seven if you count Francis) legitimate children that survived to adulthood, plus several bastards. While Mary was James V's only surviving legitimate, he fathered at least nine bastards. With this in mind, I figured it was at least possible for Francis and Mary to have five children make it to adulthood, out of numerous other miscarriages/stillbirths/early deaths. They are as follows:
Louis (b. 1562)
Marie (b. 1564)
Charles (b. 1566)
Claude (b. 1569)
Madeleine (b. 1572)
Louis and Charles, an heir and a spare, just about secure the succession. Marie and Claude aren't the most robust princesses, more like the kind to have one or two children before dying from a birth/miscarriage or being left infertile from one. Madeleine, however, is healthy as can be, unlike her ill-fated ancestor.
In 1562, Queen Elizabeth is a year or two shy of thirty, and she ain't getting any younger. Her successor is married to the King of France and a queen in her own right, and Mary's newborn son now has very good claim to three kingdoms.
How would a healthier, more independent Francis II affect the future of France? Who would Elizabeth marry to try and produce a legitimate heir? If that fails, would she seek to declare another heir in Mary/Louis's place? If that were the case, would France-Scotland be prepared to go to war over their king's rightful claim on England? Would the world see a France-Scotland-England, if only for a little while?
What about marriages and the resulting alliances? Surely such close claimants to three kingdoms would be very high in demand on the marriage market.