Thanks for your clarification. BTW: Isabel DID succeed her father as head of the imperial house; it's just that the Brazilian monarchy got abolished by then. Her situation was no different from that of other royal pretenders, who have been obliged to style themselves with lower titles (e.g. Duke of Calabria, Duke of Bavaria, Duke of Braganza, Count of Paris, Crown Prince of Serbia, Grand Duke of Russia, Duke of Württemberg, etc).

It would be rather pretentious to style oneself as a king or emperor, if the house is no longer reigning -- even if he is the undisputed head. As I understand, only a once-enthroned king (e.g. Constantine II of the Hellenes) is entitled to continue styling himself with the title, after getting deposed. It's just that he forfeits the distinction of being His Majesty THE King of X. Rather, he becomes simply His Majesty King ____ of X.

That being said, it is correct to refer to a royal claimant as the TITULAR king of a country, even if he never reigned. Case in point: Prince Ferdinando Pio, Duke of Calabria (born in 1869) was the titular King Ferdinando III of the Two Sicilies from 1934 until his death in 1960. Similarly, his brother-in-law Rupprecht (who was the same age) was the titular King of Bavaria from 1921 until his death in 1955.

By that logic, it would be justifiable to refer to Isabel as the titular Empress of Brazil. And supporters of Maria Vladimirovna's claim to headship of the Romanov imperial dynasty refer to her as the titular Empress of All Russias. As it is, the former was obliged to formally adopt the lower title of Princess Imperial, while the latter has been styled as Grand Duchess.

I've never heard of an emperor consort; but then, female succession is not normally permitted in royal houses. It seems to have been the exception throughout history, not the rule. And even in the few places where it is permitted (e.g. England, Scotland, Spain, Portugal), inheritance laws have not been gender-blind: a sovereign is always succeeded by a son, unless he has none (known as the Castilian law). Great Britain changed the law to fully cognatic primogeniture only in 2013.

It would certainly have been in keeping with Spanish and Portuguese tradition for Gaston to have been styled with a title equal to that of his wife. We have observed how husbands of queens regnant have been styled as kings consort. We have also seen how husbands of Spanish Infantas have been created into Infantes of Spain (e.g. the sons-in-law of Queen Regent Maria Cristina, brothers-in-law of King Alfonso XIII).

My question is: has any husband of a Portuguese Infanta ever been created into an Infante of Portugal? I don't believe that either of the sons-in-law of King Consort Ferdinand was ever styled thus. As it was, one of them was the future King Georg of Saxony, while the other was Leopold, Fürst of Hohenzollern-Sigmaringen.

Of course, neither ever settled in his wife's native land: both Infanta Maria Ana and Infanta Antonia left Portugal to settle in their husbands' lands -- something traditionally expected of princesses. But then, having five brothers, neither ever expected to succeed to the Portuguese throne, anyway.

It's too bad that Prince Ferdinando Pio of Bourbon-Two Sicilies, Duke of Calabria, was never created into a prince of Bavaria -- despite residing for over 60 years in his wife's native land (where he is buried). We have seen how Archduke Lorenz of Austria-Este, husband of Princess Astrid of Belgium, was eventually declared a prince of Belgium.

Then again, I realize it would not have been the German way to make an exception and thus honor Ferdinando (whose brother Carlo was created into an Infante of Spain): when in Rome, do as Romans do. At least the Bavarian government recognized the Sicilian royal titles of his children by Princess Maria Ludwiga, notwithstanding the fact that they were associated with a non-reigning house.

In this, the situation would perhaps be comparable to that of Astrid and Lorenz's children, before the Belgian constitution got amended in 1991 to change the succession law: at least their Habsburg titles were recognized. As I understand, each was styled from the beginning as Archduke/Archduchess of Austria-Este, with the qualification of Imperial and Royal Highness.