Marie-Adélaïde, Grand Duchess of Luxembourg

Marie-Adélaïde was named heiress presumptive in 1907 by her father Grand Duke William IV to head off a succession crisis - he had no son, and she would become Luxembourg's first Grand Duchess regnant and first female monarch since Duchess Maria Theresa in the eighteenth century. She inherited the throne in 1912 at seventeen. The First World War arrived two years later, and the German occupation that followed became her undoing: her perceived support for the occupiers made her deeply unpopular at home and toxic to France and Belgium. Under enormous pressure from Parliament and her own people, she abdicated on 14 January 1919 in favour of her younger sister Charlotte, who would save the monarchy in a referendum later that year. Marie-Adélaïde withdrew to a convent in Italy, left due to ill health, and died of influenza in Germany on 24 January 1924 at twenty-nine.