19 December 1888
Henry Morton Stanley, an English explorer who lived in America, was commissioned by The New York Herald with the task of finding explorer David Livingstone. No one had heard from Livingstone since he left for Africa in 1840. Finding Livingstone in 1871 brought fame for Stanley and he became known as the man who uttered the words “D.R Livingstone, I presume” upon meeting him. After finding Livingstone, Stanley continued to explore Africa and went deeper into the Congo region.
References

The Atlantic Monthly Company (1996). ‘Henry Morton Stanley (1841-1904)’ from The Atlantic Online [online]. Available at www.theatlantic.com [Accessed 5 December 2011]|Brooks, N. (2011). ‘HENRY M. STANLEY (BORN 1841)’ from Web-Books [online].  Available at www.web-books.com [Accessed 5 December 2011]