Henri Heidemanns was born in Amsterdam but worked in London as a miniature painter and lithographic printer, exhibiting at the Royal Academy 1845 – 64 from addresses in London at 68 Quadrant (1845), 10 Red Lion Square (1847), 8 Duke Street (1849) and 76 Gower Street (1864). He also exhibited at the Academy of Berlin in 1848. This miniature by Heidemanns shows Nicholas I, Emperor of Russia, lying on his deathbed with his head in profile to the left, and a military great coat drawn up around his shoulders. A signed version of this miniature by Henri Philippe Heidemanns is in the Dutch Royal Collection (Schaffers-Bodenhausen and Tiethoff-Spliethoff 1993, p. 320, no. 397) and is stated to be after a daguerreotype by Mouhot Frères (RCIN 2932512), the same source as a photographic print pasted into an album of engravings in the Royal Library, Windsor Castle (RCIN 614580). On receiving news of the Emperor's death, which had occurred on 18 February 1855, Leopold I, King of the Belgians, confided to Queen Victoria: 'It seems that the poor Empr was ill for much longer than anyone knew & that therefore his death was not so sudden' (RA VIC/Y 100/11). Queen Victoria reminisced on his passing: '11 years ago he was here – all kindness, & wonderfully fascinating & handsome' (RA QVJ: 2 March 1855).

Nicholas I, third son of Tsar Paul I and Maria Feodorovna, daughter of Frederick, Duke of Württemberg, succeeded to the throne of Russia in 1825 following the death of his eldest brother Alexander I and the renunciation of the throne by his second brother, Grand Duke Constantine. His aggressive interest in Turkey culminated in the Crimean War, which had not been concluded at the time of his death in 1855.

The Mouhot brothers were Henri (1826-61), French naturalist and explorer, and Charles (1828-95). Henri lived and worked as a teacher in St Petersburg between 1844 and 1854, the year in which he decided to travel around Europe with his brother, working together as daguerreotypists. While in The Hague in 1855, perhaps because of Henri's earlier connections with Russia, the brothers were given the task of reproducing the original daguerreotype (possibly by Sergei Levitsky) which had been sent to the Queen Dowager of the Netherlands, Anna Pavlovna of Russia (1795-1865), sister of Nicholas I, in June 1855, so that copies could be distributed to 'people of high birth and dignity' (Dr Wap (ed.), ‘Het photografisch etablissement der heeren Gebr. Mouhot, te ’s-Gravenhage’, Astrea: Maandschrift voor Schone Kunst, Wetenschap en Letteren, 5, p. 119). In 1856, the brothers moved to England where both married. Henri would then leave in 1858 to explore Indochina where he eventually died in 1861. He is chiefly remembered for his descriptions of the then virtually unknown ruins of Angkor, following the posthumous publications of his travel journals in 1863.