Ethiopia was reunified in 1855 under Tewodros II, beginning Ethiopia's modern history and his reign was followed by Yohannes IV who was killed in action in 1889. Under Menelik II Ethiopia started its transformation to well organized technological advancement and the structure that the country has now. Ethiopia also expanded to the south and east, through the conquest of the western Oromo, Sidama, Gurage, Wolayta and other groups, resulting in the borders of modern Ethiopia. Ethiopia defeated an Egyptian invasion in 1876 and an Italian invasion in 1896 which killed 17,000 Ethiopians, and came to be recognized as a legitimate state by European powers. A more rapid modernisation took place under Menelik II and Haile Selassie. Italy launched a second invasion in 1935. From 1935 to 1941, Ethiopia was under Italian occupation as part of Italian East Africa. The Allies managed to drive the Italians out of the country in 1941, and Haile Selassie was returned to the throne from his 5 years exiled in Britain. Ethiopia and Eritrea united in a federation, but when Haile Selassie ended the federation in 1961 and made Eritrea a province of Ethiopia, the 30-year Eritrean War of Independence broke out. Eritrea regained its independence after a referendum in 1993.