The two years of Menelik's reign that followed the death of Ras Tessema in 1911 found real power in the hands of Ras (later Negus) Mikael of Welo, an Oromo and former Muslim, who had converted to Christianity under duress. Mikael could muster an army of 80,000 in his predominantly Muslim province and commanded the allegiance of Oromo outside it. In December 1913, Menelik died, but fear of civil war induced the court to keep his death secret for some time. Although recognized as emperor, Menelik's nephew, Lij Iyasu, was not formally crowned. The old nobility quickly attempted to reassert its power, which Menelik had undercut, and united against Lij Iyasu. At the outbreak of World War I, encouraged by his father and by German and Turkish diplomats, Lij Iyasu adopted the Islamic faith. Seeking to revive Muslim-Oromo predominance, Lij Iyasu placed the eastern half of Ethiopia under Ras Mikael's control, officially placed his country in religious dependence on the Ottoman sultan-caliph, and established cordial relations with Somali leader Muhammad Abdullah Hassan.

The Shewan nobility immediately secured excommunicating Lij Iyasu and deposing him as emperor from the head of the Ethiopian Orthodox Church a proclamation. Menelik's daughter, Zawditu, was declared empress. Tafari Mekonnen, the son of Ras Mekonnen of Harer (who was a descendant of a Shewan negus and a supporter of the nobles), was declared regent and heir to the throne and given the title of ras. By virtue of the power and prestige he derived from his achievements as one of Menelik's generals, Habte Giorgis, the minister of war and a traditionalist, continued to play a major role in government affairs until his death in 1926. Although Lij Iyasu was captured in a brief military campaign in 1921 and imprisoned until his death in 1936, his father, Negus Mikael, continued for some time to pose a serious challenge to the government in Addis Ababa. The death of Habte Giorgis in 1926 left Tafari in effective control of the government. In 1928 he was crowned negus. When the empress died in 1930, Tafari succeeded to the throne without contest. Seventeen years after the death of Menelik, the succession struggle thus ended in favor of Tafari.

Well before his crowning as negus, Tafari began to introduce a degree of modernization into Ethiopia. As early as 1920, he ordered administrative regulations and legal code books from various European countries to provide models for his newly created bureaucracy. Ministers were also appointed to advise the regent and were given official accommodations in the capital. To ensure the growth of a class of educated young men who might be useful in introducing reforms in the years ahead, Tafari promoted government schooling. He enlarged the school Menelik had established for the sons of nobles and founded Tafari Mekonnen Elementary School in 1925. In addition, he took steps to improve health and social services.

Tafari also acted to extend his power base and to secure allies abroad. In 1919, after efforts to gain membership in the League of Nations were blocked because of the existence of slavery in Ethiopia, he (and Empress Zawditu) complied with the norms of the international community by banning the slave trade in 1923. That same year, Ethiopia was unanimously voted membership in the League of Nations. Continuing to seek international approval of the country's internal conditions, the government enacted laws in 1924 that provided for the gradual emancipation of slaves and their offspring and created a government bureau to oversee the process. The exact degree of servitude was difficult to determine, however, as the majority of slaves worked in households and were considered, at least among Amhara and Tigray, to be second-class family members.

Ethiopia signed a twenty-year treaty of friendship with Italy in 1928, providing for an Ethiopian free-trade zone at Aseb in Eritrea and the construction of a road from the port to Dese in Welo. A joint company controlled road traffic. Contact with the outside world expanded further when the emperor engaged a Belgian military mission in 1929 to train the royal bodyguards (see Training, ch. 5). In 1930 negotiations started between Ethiopia and various international banking institutions for the establishment of the Bank of Ethiopia. In the same year, Tafari signed the Arms Traffic Act with Britain, France, and Italy, by which unauthorized persons were denied the right to import arms. The act also recognized the government's right to procure arms against external aggression and to maintain internal order.

Data as of 1991