latter was out of the country. Haidalla had been at a Franco-African Summit in Burundi and learned of the coup in Brazzaville, during his return to Mauritania, from Denis Sassou Nguesso, the president of the Republic of the Congo. Haidallah returned to Mauritania anyway and was arrested at the airport in Nouakchott; he was eventually released in December 1988. Taya promised to install democracy, but his rule was considered dictatorial by many; he was deposed by a military coup in 2005. Foreign policy Haidallah's main achievement was to make peace with the Western Sahara-based Polisario Front, which had been fighting Mauritania since it annexed part of the former Spanish colony in 1975. The CMSN opted for complete withdrawal from the conflict, evacuating southern Rio de Oro (which had been annexed as Tiris El Gharbiya) and recognizing the POLISARIO as the representative of the Sahrawi people. This led to a crisis in relations with the country's until-then ally Morocco, which had similarly annexed the remainder of Western Sahara, with Haidallah's government facing an attempted coup, troop clashes and military tension. Relations were completely severed between 1981 and 1985, when they were restored by Haidalla's successor. However, relations improved with POLISARIO's main regional backer, Algeria, with the Algerian government sending arms and supplies to bolster his regime. Haidalla's 1984 recognition of the Sahrawi Arab Democratic Republic (SADR, the POLISARIO's government-in-exile) as a sovereign nation appears to have been one of the triggering causes for Maaouya Ould Sid'Ahmed Taya's coup in 1984. Domestic policy On the domestic front, his most notable policies were the institution of Islamic Sharia law in 1980-83, as well as several failed attempts to rebuild the political system shattered by the 1978 coup—first as a multiparty system, and then, after the first coup attempt against him, as a one-party state. It was also during Haidalla's rule that slavery was formally abolished in Mauritania, although the practice continues at a diminished level still today. He made a statement announcing the abolition of slavery in July 1980, and this was followed by a legal decree in November 1981. Political opponents were treated harshly, with imprisonments and those responsible for one of the failed coups against his government were executed. Activities after losing power After returning to Mauritania in 1984, Haidallah was held in administrative detention for several years by Ould Taya, during which time he fell sick. After his release, he