In 1856, the Royal Geographical Society funded another expedition for Burton and Speke, "and exploration of the then utterly unknown Lake regions of Central Africa." They would travel from Zanzibar to Ujiji along a caravan route established in 1825 by an Arab slave and ivory merchant. The Great Journey commenced on 5 June 1857 with their departure from Zanzibar, where they had stayed at the residence of Atkins Hamerton, the British consul, their caravan consisting of Baluchi mercenaries led by Ramji, 36 porters, eventually a total of 132 persons, all led by the caravan leader Said bin Salim. From the beginning, Burton and Speke were hindered by disease, malaria, fevers, and other maladies, at times both having to be carried in a hammock. Pack animals died, and natives deserted, taking supplies with them. Yet, on 7 November 1857, they made it to Kazeh, and departed for Ujij on 14 Dec Speke wanted to head north, sure they would find the source of the Nile at what he later named Victoria Nyanza, but Burton persisted in heading west.