Part of the French colonial system dating back to the nineteenth century, the territory known as the Republic of the Congo became autonomous within the French Community in 1958. Full independence followed on 15 August 1960, and the country held its first presidential elections in 1961. Longstanding ethnic tensions led to the eventual resignation of President Abbé Fulbert Youlou. The Mouvement National de la Revolution ( MNR), a Marxist-Leninist party, was established in 1964 as the sole political party in the country. Conflict between the MNR and the army led to a military coup in 1968, headed by Captain Marien Ngouabi, who had emerged as the principal player in Congolese politics. December 1969 saw the replacement of the MNR with a new Marxist-Leninist party, the Parti Congolais du Travail (PCT, Congolese Worker's Party). Ngouabi remained in power, despite increasing ethnic and political tensions, until his assassination in 1977. The new government was unable to control the military governing committee and the left wing of the powerful PCT and was forced to relinquish power to a provisional committee. In March 1979, the president of that committee, Colonel Denis Sassou-Nguesso, was appointed president of the Republic of the Congo.