O'Sullivan De Grass De Séovaud, Count Alphonse (Brussels, 8 November 1798 – Vienna, 11 January 1866), diplomat.

O’Sullivan is the son of Jean-Patrice O’Sullivan, State Counselor under King William I, and Charlotte Marie Thérèse Josephine de Grass.

In 1817 O’Sullivan is attached as a supernumerary to the Home Office. On 31 December 1818 he becomes a State Clerk at the State Council and a delegate at the Department of the Interior. On 24 September 1825 he is transferred to the Foreign Office. His diplomatic career starts in Berlin, where he is nominated legation secretary in May 1826. Then, on 14 August 1828 he moves to Saint-Petersburg. On 18 August 1831, he is honorably discharged, at his own request, when Belgium separates from Holland to become an independent nation. In December 1833 he re-enters the diplomatic service as chargé d’affaires in Vienna, where he facilitates the inauguration of Belgo-Austrian diplomatic relations. He’s promoted to resident minister on 31 March 1836. In the meantime, he marries Françoise Sévérine Barbe Joséphine Schwartz de Mohrenstern in Vienna, on 30 October 1834. In July 1837, he becomes extraordinary envoy and plenipotentiary minister.

His period in Vienna is interrupted by a special mission to Constantinople in April of 1838, where he goes to negotiate a commercial treaty with the Ottoman Sultan. Thanks to his skills as a negotiator and diplomat, he keeps the mission from being usurped by the British and French and ensures that official relations between Belgium and the Porte are opened. An important friendship and commercial treaty is signed on 3 August 1838. On 11 November 1838 O’Sullivan is awarded a baronetcy and is granted letters patent to add ‘de Séovaud’ to his name; an honorific stemming from his maternal uncle, General-Major de Séovaud de la Bastide.

On 17 March 1839, O’Sullivan is reconfirmed as envoy and minister in Vienna, but soon afterwards, on 15 July, he is charged with an extraordinary mission to the courts of Munich, Stuttgart and Karlsruhe. The purpose of this trip is to explore the possibilities for diplomatic relations and for a commercial treaty with Bavaria. He represents the Belgian government at the inauguration of the Olomouc-Prague railway on 20 August 1845 and, by letters patent of 15 October 1845, becomes a count. O’Sullivan negotiates an extradition treaty with Austria, concluded on 16 July 1853. That same year, he facilitates a treaty upholding the Duke of Brabant’s marriage to the Austrian princess Marie Henrietta, the granddaughter of Emperor Leopold II.

From the mid 1850’s onwards O’Sullivan secretly takes part in the expansionist agenda of Prince Leopold, Duke of Brabant, thus becoming a member of the broad but informal network surrounding the prince. Together they develop a daring project, though one that will remain hypothetical, consisting of a Belgian military action during the Crimean War. O’Sullivan begins to work on a new definition of the concept of neutrality; a concept that will be abandoned in exchange for territorial acquisition. The goal is that Belgium will become more independent of France through a deeper connection to the allies during the war; and that territorial expansion will be on the Rhine, at the cost of Prussia, rather than of Holland, which is what the Duke of Brabant had in mind. A second line of thought concerns the aftermath of the Crimean War, when, in O’Sullivan’s opinion, the Ottoman position will be seriously weakened, making it possible for Belgium to occupy certain parts of the empire. O’Sullivan shows himself in his correspondence with the prince to be a hardliner expansionist, willing to topple the Sultan and replace him with a Christian, preferably Catholic, king recruited in Belgium, where a tradition of political neutrality existed. A few years later, upon the Duke of Brabant’s return from Constantinople via Trieste in May 1860, O’Sullivan delivers a memorandum to the prince entitled “Mémoire sur la formation d’une compagnie belge dans l’archipel méditerranéen”. This memo comprises a scheme to occupy an island in the eastern Mediterranean (Crete or Cyprus), that will be bought or leased from the Sultan, and provides a blueprint for commercial exploitation under the protection of Leopold I, with the Duke of Brabant as president of the Board of Directors.

After the Duke of Brabant’s accession to the Belgian throne as Leopold II, O’Sullivan is reconfirmed as envoy in Vienna in December, 1865. Soon afterwards, on 11 January 1866, he dies. His funeral, held on 14 January at the Scottish Church in Vienna is attended by numerous prominent politicians and diplomats. This pomp and circumstance is not surprising, considering that O’Sullivan had been in diplomatic service for more than thirty years and was respected and valuated by everyone, not least in Austria.


Dr. Jan Anckaer
Library Federal Parliament
14 mai 2012

Unpublished sources

Foreign Office Archives, Brussels, Diplomatic personnel files, nr. 246 (O’Sullivan)

Foreign Office Archives, Brussels, Political Correspondence Austria, 1833-1865..

Royal Palace Archives, Brussels, Conway Archives, Letters from O’Sullivan to the Duke of Brabant, 1854-1864

Royal Palace Archives, Brussels, Archives of Leopold I, Cabinet of the King, Correspondence.

Royal Palace Archives, Brussels, Goffinet Archives, Archives of the private secretariat of the Duke of Brabant, Letters to and from the Duke.

State Archives of Belgium, Brussels, Rogier Papers, Letters from O’Sullivan, 1862-1865.

Scientific publications

De Borchgrave (E.), Alphonse Albert Henri comte O’Sullivan de Grass, in Biographie Nationale, XVI, 1901, col. 351-355.

De Stein d’Altenstein (I.), O’Sullivan, in Annuaire de la noblesse de Belgique, Brussels, IXL, 1887, p. 204-208.

Duchesne (A.), Rhodes : de la Cité des Chevaliers aux projets de Léopold II, in Bulletin des séances de l’Académie Royale des Sciences d’Outremer, 34, 1988, p. 407-424.

Greindl (L.),  Léopold II a envisagé l’achat de l’île de Chypre, in Cahiers léopoldiens, II, nr. 5, May 1961, p. 47-56.



Biographical Dictionary of Overseas Belgians