Two closely-written manuscripts have been preserved at the museum in Wisbech, birthplace of Thomas Clarkson, describing interviews that Clarkson conducted with Alexander I of Russia in Paris in September 1815, and in Aix-la-Chapelle in 1818. In the first interview, Alexander gave an account of his efforts to promote abolition among the European leaders at the Congress of Vienna, and promised his continuing support to the abolitionists. At their meeting three years later, Clarkson called on Alexander to back his proposal for complete abolition by 1820, and an agreement classifying slave trading as piracy. Clarkson also asked for Alexander's help in presenting abolitionist addresses to the Emperors of Prussia and Austria, and his influence in favour of Haiti, still fearful of a French re-invasion. He presented the Emperor with books and examples of African craftsmanship.

The two manuscripts were published as a pamphlet over a century later, entitled: Thomas Clarkson's Interviews with the Emperor of Russia at Paris and Aix-la-Chapelle in 1815 and 1818 as told by himself (London: Slavery and Native Races Committee of the Society of Friends, 1930). Includes foreword written by Priscilla H. Peckover and an engraving of the late nineteenth-century monument to Clarkson in Wisbech. According to the title page, "the interviews are of special interest for their references to the problems of Slavery and Peace a hundred years ago in Europe".