Prince Grégoire Bibesco-Bassaraba de Brancovan (12 December 1827 – 15 October 1886) was a Romanian-French prince.
He married Rakoul (Rachel) Musurus (born c. 1848), the daughter of PashaConstantine (‘Costaki’) Musurus (1807–1891) the Turkish ambassador to Britain. Among her extended family was uncle Anthony Asquith (a prominent English film director), aunt Elizabeth Lucy, Princess Bibesco (wife of Prince Antoine Bibesco). Her maternal grandparents were Prime Minister of the United KingdomH. H. Asquith (later 1st Earl of Oxford and Asquith) and the socialite and author Margot Asquith. They had three children:
- Prince Constantine Bibesco-Bassaraba de Brancovan (1875–1967)
- Princess Anna Elisabeth Bibesco-Bassaraba de Brancovan (1876–1933), who married Conste Mathieu Frederic Ferdinand garcal de Noailles in Paris On July 29, 1897. Anna Elizabeth was a contemporary of Marcel Proust and a prominent figure in Parisian society.
- Princess Catherine Hélène Bibesco-Bassaraba de Brancovan (1878–1929), who married Belgian Prince Alexandre de Caraman-Chimay (1873–1951), a son of Joseph de Caraman-Chimay, 18th Prince de Chimay and brother of Élisabeth, Countess Greffulhe and Joseph, Prince de Caraman-Chimay (married to American heiress Clara Ward). After Princess Hélène’s death in 1929, Prince Alexandre married Mathilde Stuyvesant (widow of American Rutherfurd Stuyvesant).
Their home, Villa Bassaraba just west of Évian at Amphion-les-Bains, was a gathering place for music and poetry lovers, including Marcel Proust, Prince Edmond de Polignac, the Princess de Polignac (formerly Winnaretta Singer, a daughter of Singer sewing machine fortune founder Isaac Singer), Prince Antoine Bibesco, and the novelist Abel Hermant.
Prince Gregoire died in Paris on 15 October 1886.