First period of military rule in NIgeria

On 15 January 1966 a group of army officers (the Young Majors) mostly southeastern Igbos, overthrew the NPC-NNDP government and assassinated the prime minister and the premiers of the northern and western regions. However the bloody nature of the Young Majors coup caused another coup to be carried out by General Johnson Aguiyi-Ironsi. The Young Majors went into hiding. Major Emmanuel Ifeajuna fled to Kwami Nkrumah's Ghana where he was welcomed as a hero. Some of the Young Majors were arrested and detained by the Ironsi government. Among the Igbo people of the Eastern Region, these detainees were heroes In the Northern Region, however, the Hausa and Fulani people demanded that the detainees be placed on trial for murder. The federal military government that assumed power under General Johnson Aguiyi-Ironsi was unable to quiet ethnic tensions on issue or other issues. Additionally, the Ironsi government was unable to produce a constitution acceptable to all sections of the country. Most fateful for the Ironsi government was the decision to issue Decree No. 34 which sought to unify the nation. Decree No. 34 sought to do away with the whole federal structure under which the Nigerian government had been organized since independence. Rioting broke out in the North The Ironsi government's efforts to abolish the federal structure and the renaming the country the Republic of Nigeria on 24 May 1966 raised tensions and led to another coup by largely northern officers in July 1966, which established the leadership of Major General Yakubu Gowon. The name Federal Republic of Nigeria was restored on 31 August 1966. However, the subsequent massacre of thousands of Igbo in the north prompted hundreds of thousands of them to return to the southeast where increasingly strong Igbo secessionist sentiment emerged. In a move towards greater autonomy to minority ethnic groups the military divided the four regions into 12 states. However the Igbo rejected attempts at constitutional revisions and insisted on full autonomy for the east. On May 29, 1967 Lt. Col. Emeka Ojukwu, the military governor of the eastern region who emerged as the leader of increasing Igbo secessionist sentiment, declared the independence of the eastern region as the Republic of Biafra on May 30, 1967.The ensuing Nigerian Civil War resulted in an estimated 3.5 million deaths (mostly from starving children) before the war ended with Gowon's famous "No victor, no vanquished" speech in 1970.

Following the civil war the country turned to the task of economic development. Foreign exchange earnings and government revenues increased spectacularly with the oil price rises of 1973-74. On July 29, 1975 Gen. Murtala Mohammed and a group of officers staged a bloodless coup, accusing Gen. Yakubu Gowon of corruption and delaying the promised return to civilian rule. General Mohammed replaced thousands of civil servants and announced a timetable for the resumption of civilian rule by October 1, 1979. He was assassinated on February 13, 1976 in an abortive coup and his chief of staff Lt. Gen. Olusegun Obasanjo became head of state.deducted from wikipedia