Believe it or not, Belgium, the tiny country you'd be unable to locate on a map, was the second most important industrial power in the world in the middle of the XIXth century.
It was thus not a negligible country, and our princesses married to crown princes of powerful nations.
However, each time, it has failed, and none of them actually became queen or empress
Empress of Mexico
Princess Charlotte, daughter of King Leopold I, married to Archduke Maximilian of Austria in 1857.
In 1862, the French invaded Mexico and tried to establish an Empire over there. They gave the crown to Maximilian and Charlotte, who were Mexican Emprerors from 1864 to 1867. (One of my ancestor was among the Belgian volunteers in Mexico!)
However, Mexican republicans took the power, Maximilian was executed and Charlotte came back to Europe.
Charlotte of Belgium - Wikipedia, the free encyclopedia French intervention in Mexico - Wikipedia, the free encyclopedia Empress of Austria
Princess Stephanie of Belgium, daughter of Leopold II, married Rudolf, crown prince of Austria. She was going to be Empress but Rudolf commited suicide with his mistress in 1889.
Princess Stéphanie of Belgium - Wikipedia, the free encyclopedia Empress of France
Princess Clementine of Belgium, third daughter of Leopold II, married to the Prince Victor Napoleon, pretender to the throne of France.
However, the 3rd French Republic never saw the revolution that would make him the new French Emperor.
Princess Clementine of Belgium - Wikipedia, the free encyclopedia Napoléon Victor Bonaparte - Wikipedia, the free encyclopedia Queen of Italy
Princess Marie José married to Umberto, crown prince of Italy. After WWII, she was queen of Italy during a month, but those **** abolished the monarchy!
Marie-José of Belgium - Wikipedia, the free encyclopedia Grand Duchess of Luxemburg
Princess Josephine Charlotte married to Jean of Luxemburg and was Grand Duchess...as you see, a Belgian princess could have ruled Mexico, Italy, Austria or France, but it worked only in Luxemburg, the only country (except Liechtenstein) that is even more insignificant than Belgium!
Joséphine-Charlotte of Belgium - Wikipedia, the free encyclopedia