Ethiopia was rapidly modernized under Emperor Haile Selassie. The later imperial shortcomings related to internal crisis and subsequent protests led the Emperor's deposition 1974 and the monarchy's abolition six months later by the Derg, a communist military government backed by the Soviet Union. Ethiopia then underwent 16 years of civil war between the Derg and Tigray-Eritrean separatist rebels as well as Somalia. In 1987, the Derg established  People's Democratic Republic of Ethiopia, a civilianized government ruled under socialist republic. Prior to dissolution of the Soviet Union, it was overthrown by the Ethiopian People's Revolutionary Democratic Front (EPRDF) on 28 May 1991, entering provisional government phase until formal government established in 1995. The EPRDF coalition, dominated by the Tigray People's Liberation Front (TPLF), marked as an authoritarian regime which brought the country into its current ethnicity-based federal system. The EPRDF coalition leadership was ended after Prime Minister Abiy Ahmed came to power in 2018, merging its parties into the new multi-ethnic Prosperity Party in 2019. Although Abiy's government initially reformed and liberated the country's politics, human rights violations, particularly ethnic unrest, heightened, sparking hostility between Abiy's government and TPLF members, leading to the ongoing Tigray War in 2020.