Question: Joseph Wolf became the preferred illustrator for this explorer who  had an obsession with discovering the sources of the Nile River 

full_context: Document 1: Joseph Smith (explorer): Joseph Smith was a British fur trader and explorer working for the Hudson's Bay Company. He was one of the first Europeans to explore the interior of what later became Canada from Hudson Bay. Smith died June 1765 en route to York Factory from the Saskatchewan country. Smith’s explorations played an important role in opening up the interior of western Canada to European trade, and his journals provide one of the earliest accounts of Cree life.
Document 2: David Livingstone: His fame as an explorer and his obsession with discovering the sources of the Nile River was founded on the belief that if he could solve that age-old mystery, his fame would give him the influence to end the East African Arab-Swahili slave trade. "The Nile sources," he told a friend, "are valuable only as a means of opening my mouth with power among men. It is this power which I hope to remedy an immense evil." His subsequent exploration of the central African watershed was the culmination of the classic period of European geographical discovery and colonial penetration of Africa. At the same time, his missionary travels, "disappearance", and eventual death in Africaand subsequent glorification as a posthumous national hero in 1874led to the founding of several major central African Christian missionary initiatives carried forward in the era of the European "Scramble for Africa".
Document 3: Nile boat: The Nile River is a major resource for the people living along it, especially thousands of years ago. The El Salha Archaeological Project discovered an abundance of evidence of an ancient boat that traveled the Nile River dating back to 3,000 years ago. Pictographs and pebble carvings were uncovered, indicating a boat more advanced than a simple canoe. This evidence of a progressed Nile boat includes a steering system which may have been used in the Nile for fishing and transportation.
Document 4: Modern Painters: Modern Painters (1843–60) is a five-volume work by the eminent Victorian art critic, John Ruskin, begun when he was 24 years old. Ruskin argues that recent painters emerging from the tradition of the picturesque are superior in the art of landscape to the old masters. The book was primarily written as a defence of the later work of J.M.W. Turner. Ruskin used the book to argue that art should devote itself to the accurate documentation of nature. In Ruskin's view, Turner had developed from early detailed documentation of nature to a later more profound insight into natural forces and atmospheric effects. It was in his 1842 visit to Switzerland that Ruskin collected material used to form the basis of Vol One.
Document 5: Adolf Bernhard Meyer: Adolf Bernhard Meyer (11 October 1840, Hamburg – 22 August 1911, Dresden) was a German anthropologist, ornithologist, entomologist, and herpetologist. He served for nearly thirty years as director of the Königlich Zoologisches und Anthropologisch-Ethnographisches Museum (now the natural history museum or Museum für Tierkunde Dresden) in Dresden. He worked on comparative anatomy and appreciated ideas from evolution, and influenced many German scientists by translating the works of Darwin and Wallace into German in 1858. Influenced by the writings of Wallace with whom he interacted, he travelled to Southeast Asia, and collected specimens and recorded his observations from the region.
Document 6: Burkhart Waldecker: Burkhart Waldecker was a German explorer who, in 1937, discovered the most southern source of the White Nile in Burundi. Waldecker came to the area to seek asylum from Nazi persecution. The true source is near Rutovu, where a pyramid was erected in 1938. Waldecker's name is seen on the plaque, which says in Latin, "Caput Nili," thus ending man's long quest to discover the source. The Nile river has various sources, Waldecker found the White Nile's most southern source which is part of the Kagera River, the other being Lake Kyoga in Uganda further north. The small pipe flowing with the first Nile water appears from the ground below the summit of Mount Kikizi where the pyramid is found.
Document 7: John Ruskin: John Ruskin (8 February 1819 – 20 January 1900) was the leading English art critic of the Victorian era, as well as an art patron, draughtsman, watercolourist, a prominent social thinker and philanthropist. He wrote on subjects as varied as geology, architecture, myth, ornithology, literature, education, botany and political economy. His writing styles and literary forms were equally varied. Ruskin also penned essays and treatises, poetry and lectures, travel guides and manuals, letters and even a fairy tale. The elaborate style that characterised his earliest writing on art was later superseded by a preference for plainer language designed to communicate his ideas more effectively. In all of his writing, he emphasised the connections between nature, art and society. He also made detailed sketches and paintings of rocks, plants, birds, landscapes, and architectural structures and ornamentation.
Document 8: Congo Free State propaganda war: The Congo Free State propaganda war was a worldwide media propaganda campaign waged by both King Leopold II of Belgium and the critics of the Congo Free State. Leopold was very astute in using the media to support his virtual private control of the nation. Edmund Dene Morel, successfully campaigned against Leopold and focused public attention on the violence of Leopold's rule. Morel used the mass media of that time, from newspapers and pamphlets to books including evidence from reports, eye-witness testimony, and pictures obtained from missionaries and others involved directly in the Congo. As Morel gained high-profile supporters, the publicity generated by his campaign eventually forced Leopold to relinquish control of the Congo to the Belgian government.
Document 9: Sándor Wolf: Alexander "Sándor" Wolf (born Eisenstadt 21 December 1871: died Haifa 2 January 1946) was an Austrian and collector of antiquities. His collection formed the basis for the museum which he founded at Eisenstadt in 1926 and which has now become the .
Document 10: William Huggins (animal artist): "Not to be confused with maritime artist William John Huggins (1781-1845)."
Document 11: John Reinhard Weguelin: John Reinhard Weguelin {'1': ", '2': ", '3': 'RWS', '4': "} (June 23, 1849 – April 28, 1927) was an English painter and illustrator, active from 1877 to after 1910. He specialized in figurative paintings with lush backgrounds, typically landscapes or garden scenes. Weguelin emulated the neo-classical style of Edward Poynter and Lawrence Alma-Tadema, painting subjects inspired by classical antiquity and mythology. He depicted scenes of everyday life in ancient Greece and Rome, as well as mythological subjects, with an emphasis on pastoral scenes. Weguelin also drew on folklore for inspiration, and painted numerous images of nymphs and mermaids. His subjects were similar to those of his contemporary, John William Waterhouse, who also specialized in painting the female figure against dramatic backgrounds, but unlike Waterhouse, many of Weguelin's subjects are nude or scantily-clad. Weguelin was particularly noted for his realistic use of light.
Document 12: Nile Expedition: The Nile Expedition, sometimes called the Gordon Relief Expedition (1884–85), was a British mission to relieve Major-General Charles George Gordon at Khartoum, Sudan. Gordon had been sent to the Sudan to help Egyptians evacuate from Sudan after Britain decided to abandon the country in the face of a rebellion led by self-proclaimed Mahdi, Mahommed Ahmed. A contingent of Canadians was recruited to help the British navigate their small boats up the Nile River. The Nile Expedition was the first overseas expedition by Canadians in a British imperial conflict, although the Nile Voyageurs were civilians employees and did not wear uniforms.
Document 13: William Yellowlees: William Yellowlees was a Scottish painter, born at Mellerstain in 1796. He came to Edinburgh in 1812, and studied there under William Shiels, the animal painter. He began practice as a portrait painter and soon became popular, winning the sobriquet of "the little Raeburn", partly by the small size, but more by the excellence of his work. He painted in Edinburgh for about fifteen years, and then moved to London, where he met with much success. Prince Albert was among his patrons. He contributed twenty portraits to the Royal Academy between 1829 and 1845. He died in London in 1855. There is a portrait by him in the Scottish National Portrait Gallery. This self-portrait was identified by a descendant of William Yellowlees, Scottish psychiatrist and musician Alexander John Yellowlees, in the 1970s whilst attending medical school in Edinburgh.
Document 14: Olaudah Equiano: Olaudah Equiano (c. 1745 – 31 March 1797), known in his lifetime as Gustavus Vassa ( ), was a prominent African in London, a freed slave who supported the British movement to end the slave trade. His autobiography, published in 1789, helped in the creation of the Slave Trade Act 1807 which ended the African trade for Britain and its colonies.
Document 15: Joseph Wolf: Joseph Wolf (21 January 1820 – 20 April 1899) was a German artist who specialized in natural history illustration. He moved to the British Museum in 1848 and became the preferred illustrator for explorers and naturalists including David Livingstone, Alfred Russel Wallace and Henry Walter Bates. Wolf depicted animals accurately in lifelike postures and is considered one of the great pioneers of wildlife art. Sir Edwin Landseer thought him "...without exception, the best all-round animal artist who ever lived"'.
ground_truth: David Livingstone