A trained economist, Donatus directs the Hessische Hausstiftung, a foundation established to curate and showcase the cultural heritage and history of the House of Hesse, a dynasty which ruled the Electorate of Hesse-Cassel until 1866, the Grand Duchy of Hesse and by Rhine until 1918, and whose male-line descendants include the Protestant leader Philip the Magnanimous, the Swedish king Frederick I, Russia's last tsarina Alexandra Feodorovna, the exiled Spanish queen Victoria Eugenie of Battenberg, and Britain's last viceroy of India, the assassinated Louis, Earl Mountbatten of Burma. Donatus also manages Prinz von Hessen, a winery specializing in production of varietal vintages on his 45 hectare vineyard. Prince Donatus' father became the head of the Hesse-Cassel line on the death of his own father, Landgrave Philip in 1980. Having also been the adopted son and heir of his distant cousin, Louis, Prince of Hesse and by Rhine, the latter's death in 1968 as the last male of the Hesse-Darmstadt branch left Moritz head of the entire House of Hesse, to which Donatus is the successor.
Marriage and issue
Donatus married Countess Floria Franziska Marie-Luisa Erika von Faber-Castell in a civil ceremony in Wiesbaden on 25 April 2003. The bride is a communications professional and a niece of Count Anton Wolfgang von Faber-Castell, chairman of the board of the famous Faber-Castell pen-and-pencil company headquartered near Nuremberg and scion of the eponymous family, which is a morganatic branch of Castell-Rüdenhausen Princely family. Prince Donatus and Floria Franziska are 6th cousins, as both descended from Frederick II, Landgrave of Hesse-Kassel and his first wife Princess Mary of Great Britain. The couple's religious wedding ceremony took place on 17 May 2003, attended by royalty and aristocrats. Held at the Johanneskirche and followed by a grand ball in the Green Salon, state room of the former Friedrichshof palace in Kronberg where Donatus's ancestress, the German Empress Frederick, lived in widowhood, more than 300 guests were present. Among them was Caroline, Princess of Hanover, the heiress presumptive of Monaco; Princess Benedikte of Denmark, aunt of the bridegroom and sister of Queens Margrethe II and Anne-Marie of Greece; and Gloria, Princess of Thurn and Taxis. Landgrave Donatus and his wife have a daughter and two sons, Princess Paulina and Hereditary Prince Moritz and Prince August.
Founded in 1928, the Foundation of the House of Hesse is the successor institution of a family trust that had been established in 1830, confiscated by the Kingdom of Prussia in 1866, and re-established after partial restitution in 1878. The foundation manages the family fortunes including forests, agricultural estates, castles, hotels and an art collection. The latter is mainly shown at Fasanerie Palace in Eichenzell, Hesse, a former summer palace of the Prince Abbots of Fulda that had been taken over by the Landgraves of Hesse after the secularization and mediatisation of the Prince-bishopric of Fulda in 1803. Schlosshotel Kronberg and Grandhotel Hessischer Hof in Frankfurt are hotels, the Weingut Prinz von Hessen a winery in Johannisberg which was purchased in 1957, while Schloß Wolfsgarten south of Frankfurt am Main and Panker estate are used as private seats of the family. Other castles have been sold, such as Schloss Philippsruhe in Hanau, Schloss Rumpenheim in Offenbach am Main and Tarasp Castle in Switzerland.