Eugene Jean, Count Of Soissons

The only son of Emmanuel Thomas, Count of Soissons (a member of the House of Savoy-Carignano), and Princess Maria Theresia of Liechtenstein, Duchess of Troppau, he succeeded his father on his death in 1729, while remaining his mother's heir apparent and being often also styled "Duke of Troppau".

In the same year 1729, the King of Sardinia Victor Amadeus II granted him the title of knight of the Supreme Order of the Most Holy Annunciation, the highest Savoy distinction.

In 1731, at the instigation of his great-uncle, Prince Eugene of Savoy, a famous general and eminent personality in the imperial court, he was made, like his father before him, knight of the Order of the Golden Fleece by the Emperor Charles VI.

With the aim of establishing a second Savoy state in central Italy, Prince Eugene of Savoy, particularly attached to his great-nephew, who was his last living male heir, requested for him the hand of Maria Teresa Cybo-Malaspina, Duchess of Massa and Princess of Carrara, obtaining the approval of Emperor Charles VI and the King of Sardinia, Charles Emmanuel III of Savoy, whom he looked to as the head of the family. The duchess was then only seven years old and was under the regency of her mother Ricciarda Gonzaga di Novellara [it]. Matrimonial agreements were signed in Vienna, where the prince resided, on 2 May 1732, and, in the month of October, the eighteen-year-old betrothed visited Massa to pay homage to his little fiancée and future mother-in-law. The marriage, however, could not take place due to the young count's premature death in Mannheim, where he was serving the emperor in the military, on 23 November 1734. Maria Teresa would later be married to Ercole Rinaldo d'Este, heir of the duchy of Modena and Reggio (and future duke under the name Ercole III).

With Eugene Jean's death, the title "Count of Soissons" became extinct and reverted to the French crown. The huge inheritance of Prince Eugene, who died intestate two years later, fell to his closest surviving relative, Eugene Jean's aunt, Anna Victoria of Savoy. In 1772, upon the death of Eugene Jean's mother, the duchy of Troppau returned to the possession of the princes of Liechtenstein, in the person of Franz Joseph I.^{[citation needed]}