and EMLF created the Union of Ethiopian Proletarian Organizations. In April 1990 the TPLF formed the Ethiopian Democratic Officers Movement from politically re-educated captured Ethiopian officers to undercut the Free Officers Movement formed in 1987 by exiled Ethiopian officers in opposition to the Derg. In May 1990 Oromo-members of the EPDM and politically re-educated Oromo-Prisoners-of-War founded the Oromo Peoples' Democratic Organization (OPDO) to deny the Oromo Liberation Front the claim to be the exclusive representative of the Ethiopian Oromo. In November 1990 an Oromo Marxist-Leninist Movement was established within the OPDO. Also in 1990 the TPLF created the Afar Democratic Union to undercut the Afar movements. Before 1985 it had already helped to establish liberation fronts in Gambella and Benshangul. In early 1988, the EPLF and the TPLF went on the offensive. The developing situation in both Eritrea and Tigray but also the shifting international context after the demise of the Soviet bloc induced the TPLF and EPLF to put their differences aside and to resume military cooperation. In 1989 the EPRDF formed a shadow government of Ethiopia administering the liberated areas under its control. 1991–2018 In February 1991 the EPRDF launched its offensive against the governing regime assisted by a large EPLF contingent. On 28 May 1991, the EPRDF entered Addis Ababa, the capital of Ethiopia, and assumed control of Ethiopia. In July 1991, the EPRDF established the Transitional Government of Ethiopia. In May 1991, the TPLF had 80,000 fighters, the EPDM 8,000 and the OPDO 2,000. The total number of TPLF-members was well beyond 100,000. Reacting to the international political context after the demise of communism, the EPRDF and TPLF dropped all Marxist references in their political discourse and adopted a program of change based on multi-party politics, constitutional democracy, ethno-linguistic federalization and a mixed economy. Under the EPRDF, Ethiopia was governed as an ethnically federal, dominant-party state. Meles Zenawi, a member of the TPLF, served as Prime Minister until his death in 2012. During EPRDF rule, Ethiopia retained authoritarianism and shifted from a one-party state to a dominant-party state. In opposition: 2018–2020 In November 2019, Prime Minister Abiy Ahmed and the Ethiopian People's Revolutionary Democratic Front chairman unified the constituent parties of the coalition into a new Prosperity Party. The TPLF viewed this merger as illegal and did not participate in the merger. From the start of January 2020, the TPLF were involved in activities that were