Ostend Manifesto, document drawn up in Oct., 1854, at Ostend, Belgium, by James Buchanan, American minister to Great Britain, John Y. Mason, minister to France, and Pierre Soulé, minister to Spain. William L. Marcy, Secretary of State under President Pierce, instructed Soulé to try to buy Cuba from Spain, but Soulé antagonized the Spanish by his political intrigues and aggressive threats (he issued an unwarranted ultimatum to the Spanish government on the Black Warrior affair). Pierce then ordered a conference of the three diplomats in Europe, all proslavery Democrats, at Ostend. The resulting manifesto strongly suggested that the United States should take Cuba by force if Spain refused to sell. Southerners, who had long feared that Cuba might become an independent black republic, applauded the document, but it was vigorously denounced by the free-soil press as a plot to extend slavery. Marcy immediately repudiated it for the U.S. government.