Henry Morton Stanley the source of the Nile. Between 1875 and 1876 Stanley succeeded in the first part of his objective, establishing that Lake Victoria had only a single outlet – the one located by John Hanning Speke on 21 July 1862. If this was not the Nile's source, then the massive northward flowing river called by Livingstone, the Lualaba, and mapped by him in its upper reaches, might flow on north to connect with the Nile via Lake Albert and thus be the primary source. It was therefore essential that Stanley should trace the course of the Lualaba downstream (northward) from Nyangwe,
John Hanning Speke Grant reached Gondokoro in Southern Sudan, where he met Samuel Baker and his "wife". (Her name was Florence von Sass and she had been rescued by Baker from a slave market in Vidin during a hunting trip in Bulgaria.) Speke had expected to meet John Petherick and his wife Katherine at Gondokoro, as they had been sent by the RGS south along the Nile to meet Speke and Grant. However the Pethericks were not there but on a side expedition to trade ivory, as they had run out of funds for their expedition. This caused some hard feelings between Pethrick