Party). The 1960s and early 1970s saw the continued and persistent violating of Senegal's borders by the Portuguese military from Portuguese Guinea. In response, Senegal petitioned the United Nations Security Council in 1963, 1965, 1969 (in response to shelling by Portuguese artillery), 1971 and finally in 1972. 1980 to present In 1980, President Senghor decided to retire from politics. The next year, he transferred power in 1981 to his hand-picked successor, Abdou Diouf. Former prime minister Mamadou Dia, who was Senghor's rival, ran for election in 1983 against Diouf, but lost. Senghor moved to France, where he died at the age of 95. In the 1980s, Boubacar Lam discovered Senegalese oral history that was initially compiled by the Tuculor noble, Yoro Dyâo, not long after World War I, which documented migrations into West Africa from the Nile Valley; ethnic groups, from the Senegal River to the Niger Delta, retained traditions of having an eastern origin. Senegal joined with The Gambia to form the nominal Senegambia Confederation on 1 February 1982. However, the union was dissolved in 1989. Despite peace talks, a southern separatist group (Movement of Democratic Forces of Casamance or MFDC) in the Casamance region has clashed sporadically with government forces since 1982 in the Casamance conflict. In the early 21st century, violence has subsided and President Macky Sall held talks with rebels in Rome in December 2012. Abdou Diouf was president between 1981 and 2000. He encouraged broader political participation, reduced government involvement in the economy, and widened Senegal's diplomatic engagements, particularly with other developing nations. Domestic politics on occasion spilled over into street violence, border tensions, and a violent separatist movement in the southern region of the Casamance. Nevertheless, Senegal's commitment to democracy and human rights strengthened. Abdou Diouf served four terms as president. During the Gulf War, over 500 Senegalese participated in the Battle of Khafji and the unexpected Liberation of Kuwait campaign, under the command of the U.S.-led coalition. In the presidential election of 1999, opposition leader Abdoulaye Wade defeated Diouf in an election deemed free and fair by international observers. Senegal experienced its second peaceful transition of power, and its first from one political party to another. On 30 December 2004 President Wade announced that he would sign a peace treaty with the separatist group in the Casamance region. This, however, has yet to be implemented. There was a round of talks in 2005,