The propensity for cooperation among East African states predates the era of self-rule in the three founding nations that formed the original East African Community (EAC) in 1967.
First, there was the 1917 Customs Union for Kenya and Uganda to which Tanganyika subscribed in 1927. Then there was the 1948-1961 East African High Commission followed by the East African Common Services Organisation founded in 1961.