Henry Morton Stanley's first trans-Africa exploration for and successfully found the missionary and explorer Livingstone, greeting him with the famous (though disputed) words: “Dr. Livingstone, I presume?” Stanley's journey had four principal aims, to: There was controversy among earlier explorers as to whether these lakes and rivers were connected to each other and the Nile. Richard Burton thought that Lake Victoria might have a southern inlet, possibly from Lake Albert, meaning that the source of the Nile was not Lake Victoria as Speke had argued. Samuel Baker thought that Lake Albert might have an inlet from Lake Tanganyika. Livingstone thought that Lualaba was the source of
Hamites races were too broad to have stemmed from a single common ancestor, but were instead consistent with separate racial origins. In his "Crania Aegyptiaca" (1844), Morton analyzed over a hundred intact crania gathered from the Nile Valley, and concluded that the ancient Egyptians were racially akin to Europeans. His conclusions would establish the foundation for the American School of anthropology, and would also influence proponents of polygenism. In the second half of the 19th century, the British explorer John Hanning Speke would further popularize the ancient Hamitic peregrinations in his publications on his search for the source of the Nile