Burton and Speke made it back to Zanzibar on 4 March 1859, and left on 22 March for Aden. Speke immediately boarded for London, where he gave lectures, and was awarded a second expedition by the Society. Burton arrived London on 21 May, discovering "My companion now stood forth in his new colours, and angry rival." Speke additionally published "What Led to the Discovery of the Source of the Nile" (1863), while Burton's "Zanzibar; City, Island, and Coast" was eventually published in 1872.