European exploration of the interior began in the mid-19th century. In 1848 the German missionary Johannes Rebmann became the first European to see Mount Kilimanjaro. British explorers Richard Burton and John Speke crossed the interior to Lake Tanganyika in June 1857. In January 1866, the Scottish explorer and missionary David Livingstone, who crusaded against the slave trade, went to Zanzibar, from where he sought the source of the Nile, and established his last mission at Ujiji on the shores of Lake Tanganyika. After having lost contact with the outside world for years, he was found there on 10 November 1871. Henry Morton Stanley, who had been sent in a publicity stunt to find him by the New York Herald newspaper, greeted him with the now famous words Dr Livingstone, I presume? In 1877, the first of a series of Belgian expeditions arrived on Zanzibar. In the course of these expeditions, in 1879 a station was founded in Kigoma on the eastern bank of Lake Tanganyika, soon to be followed by the station of Mpala on the opposite western bank. Both stations were founded in the name of the Comite D'Etudes Du Haut Congo, a predecessor organization of the Congo Free State. German colonial interests were first advanced in 1884.: Karl Peters, who formed the Society for German Colonization, concluded a series of treaties by which tribal chiefs ceded territory to the society.: Prince Otto von Bismarck's government in 1885 granted imperial protection to the German East Africa Company established by Peters with Bismark's encouragement.: