From 1930 until 1974, Ethiopia was under the rule of Haile Selassie, who had served as the Regent Plenipotentiary of Ethiopia since the year 1916. A key figure in Ethiopian history, he also played a significant role in the emergence of Rastafari, a Jamaican religious movement born in the 1930s when he assumed the title of Emperor. As a member of the Solomonic dynasty, claiming lineage from Emperor Menelik I, the son of King Solomon and Queen Makeda of Sheba, Haile Selassie held a unique place in Ethiopia's historical narrative.
In his quest for modernization, Haile Selassie introduced political and social reforms, such as Ethiopia's first written constitution in the year 1931 and the abolition of slavery. He actively led Ethiopia during the Second Italo-Ethiopian War, facing the Italian occupation and later residing in exile in England. After the defeat of the Italians by the British Empire in the year 1941, Haile Selassie returned to govern Ethiopia. He dissolved the Federation of Ethiopia and Eritrea, established by the United Nations General Assembly in the year 1950, integrating Eritrea as a province of Ethiopia while opposing secession.
Haile Selassie's internationalist vision led Ethiopia to become a founding member of the United Nations. He served as the inaugural chairman of the Organisation of African Unity, precursor to the African Union, established in the year 1963. However, in the year 1974, the Derg, a Marxist–Leninist junta, orchestrated a military revolution, overthrowing Haile Selassie, who met his demise on August 27, 1975.