France
A Change of Dynasty
Who should choose the new king? France had no mechanism for such a thing and scarcely any institutions. Parlements were called into existence by the king and their powers were mainly judicial. Estates could be called by the king or by a duke, but they mainly approved taxes or heard petitions. There was nothing even remotely like the assembly of barons in the English Parliament, and still less like the German Electors. So something new had to be invented, or something old put to a new use. Whatever was chosen would tend to predispose the body towards one sort of choice or another.
For the range of possibilities was wide and extended well beyond France itself. Blood mattered far more than nationality at a time when nationality barely even existed as a concept. A new king might be French, but he might equally well be Provençal or Flemish or German. Or English.
In the end, a special committee of review decided that blood relation mattered a great deal and, in a fateful decision, it decided that the crown of France could pass only through the male line. At first glance, this sounds like a standard sexist decision in favor of men, but the real issue was national. If the nobles and lawyers had allowed the crown to pass through either line, then Edward of England's claim was closer than any Frenchman's, and that was simply intolerable. The French nobility were going to choose a French lord and they would simply manipulate the law to settle the matter as they wished.
In the event, they found some precedent in ancient customs among the Salians, a branch of the Frankish tribes who founded France. With a fine, noble, and ancient precedent in Salian Law, the lords of France proclaimed with great solemnity that the crown could never be passed through a female line. With that to buttress them, they proceeded to choose the noble who was most closely related to the Capetians via the male line, Philip of Valois, who also happened to be the richest of all the French nobility. Everything had been neatly worked out, with one exception: Edward of England disputed the claim.