Prince Franz Alexander, 9th Prince of Isenburg (1943-2018) (1943–2018) Parents Irina Tolstaya Franz Ferdinand, Prince of Isenburg Children Prince Alexander, 10th Prince of Isenburg Prince Viktor of Isenburg Archduchess Katharina, Archduchess Martin of Austria-Este Sophie, Princess of Prussia Isabelle, Princess of Wied Siblings Irene Prinzessin von Isenburg Maria Annunciata Prinzessin von Isenburg Elisabeth Prinzessin von Isenburg Partners Christine, Countess von Saurma