- King Louis XIX (Louis-Antoine of France)
- France ()
In July 1830, Louis-Antoine of France – the last “Dauphin”, or heir apparent – ascended the French throne as King Louis XIX, succeeding his father, Charles X, who had abdicated. Within 20 minutes, however, Louis-Antoine had also abdicated, making him the joint shortest reigning monarch in history. He shares the record with the unfortunate Crown Prince Luís Filipe of Portugal, who technically became King of Portugal for the same brief period following the assassination of his father, Dom Carlos I, on 1 February 1908. Luís Filipe was himself fatally wounded in the attack, but he survived his father by 20 minutes.