Historically, Charles VI of France is one of the most literally mad kings ever, since he had crises of hallucinations, regularly thought he was made of glass, and other similar things.
While it is true that Charles had a strong genetic predisposition to madness - it ran in his mother's family and he had been born from some consanguinity to the point that he was almost the only one of 9 children to have survived to adult age - it only really kicked in after falling from his horse, and taking a blow to the head in the process.
Charles VI's madness led to a total disaster for the Kingdom of France : England, reduced to the cities of Bordeaux, Bayonne, Brest and Calais, was able to recapture with the help of the Bourguignon party most of Northern France and Aquitaine, with the nominal ownership of all of France at the treaty of Troyes.
So. What would happen if Charles VI, whose early personal reign had been fairly successful in a truce with England, hadn't gotten mad, giving way to the Armagnac/Bourguignon civil war?
While it is true that Charles had a strong genetic predisposition to madness - it ran in his mother's family and he had been born from some consanguinity to the point that he was almost the only one of 9 children to have survived to adult age - it only really kicked in after falling from his horse, and taking a blow to the head in the process.
Charles VI's madness led to a total disaster for the Kingdom of France : England, reduced to the cities of Bordeaux, Bayonne, Brest and Calais, was able to recapture with the help of the Bourguignon party most of Northern France and Aquitaine, with the nominal ownership of all of France at the treaty of Troyes.
So. What would happen if Charles VI, whose early personal reign had been fairly successful in a truce with England, hadn't gotten mad, giving way to the Armagnac/Bourguignon civil war?