Which realistic cases were there where a cadet branch could have inherited a country's throne but didn't? I can think of:
-If French King Francis I is killed at Marignano in 1515, then the French throne will pass to Charles IV, Duke of Alencon and then to Charles III, Duke of Bourbon once Alencon will die childless. Charles III, Duke of Bourbon came from the elder branch of the House of Bourbon, which became extinct upon his death in 1527 (which won't occur if he's already the French King during this time); meanwhile, the OTL later French royal Bourbons came from the junior Bourbon-Vendome branch, descended from James I, Count of La Marche, the younger brother of Peter I, Duke of Bourbon, who lived back in the 14th century.
-If then-Italian Crown Prince Umberto is assassinated in 1928 by this guy: Fernando de Rosa - Wikipedia , then the junior Savoy-Aosta branch will inherit the Italian throne upon Victor Emmanuel III's abdication in 1946. So, this guy would be the Italian King for a month instead of Umberto II: Prince Aimone, Duke of Aosta - Wikipedia And this is assuming that the 1946 Italian monarchy referendum would have actually had the same outcome in this TL as it actually had in real life.
-If French King Louis XV will die in or before 1728, then the French throne will pass on to Louis I, Duke of Orleans, who is descended in the male line from Philippe I, Duke of Orleans, the gay younger brother of French King Louis XIV, who was Louis XV's great-grandfather.
Anyway, which additional realistic examples of this can you think of?
-If French King Francis I is killed at Marignano in 1515, then the French throne will pass to Charles IV, Duke of Alencon and then to Charles III, Duke of Bourbon once Alencon will die childless. Charles III, Duke of Bourbon came from the elder branch of the House of Bourbon, which became extinct upon his death in 1527 (which won't occur if he's already the French King during this time); meanwhile, the OTL later French royal Bourbons came from the junior Bourbon-Vendome branch, descended from James I, Count of La Marche, the younger brother of Peter I, Duke of Bourbon, who lived back in the 14th century.
-If then-Italian Crown Prince Umberto is assassinated in 1928 by this guy: Fernando de Rosa - Wikipedia , then the junior Savoy-Aosta branch will inherit the Italian throne upon Victor Emmanuel III's abdication in 1946. So, this guy would be the Italian King for a month instead of Umberto II: Prince Aimone, Duke of Aosta - Wikipedia And this is assuming that the 1946 Italian monarchy referendum would have actually had the same outcome in this TL as it actually had in real life.
-If French King Louis XV will die in or before 1728, then the French throne will pass on to Louis I, Duke of Orleans, who is descended in the male line from Philippe I, Duke of Orleans, the gay younger brother of French King Louis XIV, who was Louis XV's great-grandfather.
Anyway, which additional realistic examples of this can you think of?