Its well known that the marriage of Ferdinand of Aragon and Isabella of Castille united modern-day Spain. However, the union came close to being undone-Isabella died in 1504, and the throne of Castille passed to her and Ferdinand's daughter, Juana the Mad, and her husband, Phillip II of Burgundy. Ferdinand had a strong dislike of Phillip and did not want him to inherit Aragon when he died, so he remarried to a French noblewoman, Germaine of Foix, and tried to have a son with her (who would be in line to inherit Aragon, but not Castille). Their efforts were unsuccessful, and when Ferdinand died in 1516, Aragon reverted to Phillip and Juana's son Charles V, thus sealing the union of Aragon and Castille.
So, what if Ferdinand and Germaine had had a son? What would the effects of an indepedent Aragon, with dynastic connections to French nobility, be on history?