In 1889 Jackson led an IBEAC expedition that included his friend and fellow explorer
Arthur Neumann in the party designed to open up the regions between
Mombasa and
Lake Victoria, which was largely unknown to Europeans at that time, and if possible to obtain news of
Emin Pasha. At
Kavirondo he received a letter from King
Mwanga II of Buganda in Uganda describing a state of great confusion there owing to rivalry between different Christian factions. He went north, exploring the country beyond
Mount Elgon. On his return to Kavirondo he found that the German
Karl Peters had passed him and raised the German flag, which he pulled down. He went on to Uganda where he found the
Baganda uncertain about whether to accept an IBEAC administration. The decision was made for them by the Heligoland treaty of 1900 in which Britain was given Uganda. and knighted as a Knight Commander (KCMG) of the same order in 1913. He retired in 1917. ==Naturalist==