Deeply impressed with the advantages of medical training to a missionary, he resolved to qualify himself in medicine, as well as the other attainments looked for in a missionary. The London Missionary Society having accepted the offer of his services, he went to London to complete his studies. His first desire was to labor in China, but, war having broken out between that country and Great Britain, this wish could not be fulfilled. The Rev. Robert Moffat's visit at this time to England turned many hearts to Africa--Livingstone's among the rest; ultimately he was appointed to that field, and, having been ordained on November 20, 1840, he set sail for Africa, reaching Lattakoo or Kuruman, Moffat's settlement, on July 31, 1841. For several years Livingstone labored as a missionary in the Bechuana country, at Mabotse, Chonuana, and Kolobeng, places that were chosen by him just because they were in the heart of heathenism. The conversion of Sechélé, chief of the Bakwains, and several of his tribe, was a great encouragement. Repulsed by the Boers in an effort to plant native missionaries in the Transvaal, he directed his steps northward, discovered Lake 'Ngami and found the country there traversed by fine rivers and inhabited by a dense population. His anxiety to benefit this region led finally to his undertaking to explore the whole country westward to the Atlantic at St. Paul de Loanda, and eastward to the Indian Ocean at Quilimane. Livingstone had married at Mabotse, Mary, eldest daughter of the Rev. R. Moffat, and now he found it necessary to send her, with their children, to England, that he might be free for this vast and perilous undertaking. To accomplish it occupied from June 8, 1852, when he left Cape Town, to May 26, 1856, when he arrived at Quilimane. This journey was accomplished with a mere handful of followers, and a mere pittance of stores, amid sicknesses and other bodily troubles, perils, and difficulties without number. But a vast amount of valuable information was gathered respecting the country and its products, its geography and natural history, the native tribes, the regions that were favorable to health, and some great natural wonders, such as the Zambesi Falls. Livingstone, however, found that the London Missionary Society were not willing that he should be to so large an extent an explorer, and some time after returning to Britain he resigned his office as one of their missionaries.