Prince Sixtus
Prince Sixtus around 1930
Born	(1886-08-01)1 August 1886 Wartegg, Canton of St. Gallen, Switzerland
Died	14 March 1934(1934-03-14) (aged 47) Paris, France
Burial	Souvigny Abbey
Spouse	Hedwig de la Rochefoucauld
Issue	Princess Isabella
Names Sixtus Ferdinand Maria Ignazio Alfred Robert
Father	Robert I, Duke of Parma
Mother	Infanta Maria Antonia of Portugal

Prince of Bourbon-Parma (given names: Sixtus Ferdinand Maria Ignazio Alfred Robert; Wartegg, Canton of St. Gallen, Switzerland, August 1, 1886 – Paris, March 14, 1934) was a son of Robert I, the last reigning duke of Parma and of his second wife Maria Antonia of Portugal. He was a prince of the House of Bourbon-Parma; a Belgian officer in World War I; and the central figure in the Sixtus Affair. He also wrote a number of books.

Sixtus was the eldest son of the last Duke of Parma, Robert I (1848–1907) and his second wife Infanta Maria Antonia of Portugal (1862–1959), daughter of King Miguel of Portugal. His father had had twelve children from his previous marriage and Sixtus was the fourteenth of Duke Robert's twenty four children. Among the twenty four, he was the sixth son, hence he was named, Sixtus.

Sixtus' father had been deposed from the Duchy of Parma during the wars of Italian unification, but having inherited the large fortune of his childless uncle, Henri, Count of Chambord. Duke Robert was very wealthy and raise his large family between Villa Pianore (a large property located between Pietrasanta and Viareggio) and his castle in Schwarzau in lower Austria. Prince Sixtus was educated at Stella Matutina, a Catholic boarding school for boys run by Jesuits priest in Feldkirch, near the Swiss border. After finishing high school, he studied law in Paris. The death of his father, in 1907, split the family. The largest part of the family's fortune was inherited by Elias, Duke of Parma, the only healthy among Sixtus' half-brothers. In 1910, the two sides of the family reached and agreement dividing their father's assets. The following year, his sister Princess Zita married Archduke Charles, the heir to the throne of the Austro-Hungarian Empire, who had been Sixtus' childhood friend.

The outbreak of World War I further split the family. Although their ancestors had reigned in Parma, the brothers had even stronger ties with both France and Austria. Unable to fight with French army Prince Sixtus and his brother Xavier joined the Belgian army while their brothers Elias, Felix and Rene fought on the opposite side for Austria where their sister Zita became empress consort in November 1916.

On March 14, 1919 Sixtus married in Paris Hedwige de La Rochefoucauld (1896–1986), daughter of Armand de La Rochefoucauld, Duke of Doudeauville, and his wife Princess Louise Radziwill. On the occasion of their marriage, the family acquired the Bourbon-Parma tiara from Chaumet. ^[1]

They had one daughter, princess Isabella Marie Antoinette Louise Hedwig (1922-2014), who in 1943 married Count Roger Alexander Lucien de la Rochefoucauld (1915–1970, murdered), son of Count Pierre Paul (1887–1970) and his wife Henriette Marguerite Marie de la Roche (1892–1980).

During World War I Sixtus and his brother Xavier enlisted in the Belgian Army. Several of their older brothers were officers in the Austrian Army. His sister Zita married Archduke Charles of Austria, who became the Austrian Emperor on November 21, 1916.

In 1917, Emperor Charles I secretly entered into peace negotiations with France, with his brother-in-law Sixtus as intermediary, without the knowledge of his ally Germany. When news of the overture leaked in April 1918, Charles I denied involvement until the French prime minister Georges Clemenceau published letters signed by him. This led to an even more dependent position of Austria with respect to its German ally. This is known as the Sixtus Affair.

• In Nordostarabien und Südmesopotamien: Vorbericht über die Forschungsreise 1912, with Alois Musil (Vienna: 1913).
• Le Traité d'Utrecht et les lois fondamentales du royaume (Paris: E. Champion, 1914). Reprinted (Paris: Communication & Tradition, 1998).
• L'offre de paix séparée de l'Autriche, 5 décembre 1916 - 12 octobre 1917 (Paris: Plon, 1920). English translation: Austria's Peace Offer, 1916-1917 (London: Constable, 1921).
• La dernière conquête du roi Alger, 1830 (Paris: Calmann-Lévy, 1930).

The television series The Young Indiana Jones Chronicles presents Sixtus (played by Benedict Taylor) and his brother Xavier (played by Matthew Wait) as Belgian officers in World War I who help the young Indiana Jones. Sixtus and his brother Xavier and the Sixtus Affair are the central subjects of the historical fiction novel "Kingdoms Fall - The Laxenburg Message" by Edward Parr.^[2]

• encyclopedia.com

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