Between 1960 and 1972, a succession of military coups brought about many changes of government. The last of these brought to power Major Mathieu Kerekou as the head of a regime professing strict Marxist-Leninist principles. The Revolutionary Party of the People of Benin (PRPB) remained in complete power until the beginning of the 1990s. Kerekou, encouraged by France and other democratic powers, convened a national conference that introduced a new democratic constitution and held presidential and legislative elections. Kerekou's principal opponent at the presidential poll, and the ultimate victor, was Prime Minister Nicephore Soglo. Supporters of Soglo also secured a majority in the National Assembly.