Siaka Probyn Stevens was the third prime minister of Sierra Leone from 1967 to 1971 and the first president of Sierra Leone from 1971 to 1985. Stevens is generally criticised for being a dictator. On a positive note, he reduced the ethnic polarisation in the government of Sierra Leone by incorporating members of various ethnic groups into the government.Stevens and his All People's Congress (APC) party won the closely contested 1967 Sierra Leone general elections over the incumbent Prime Minister Sir Albert Margai of the Sierra Leone People's Party (SLPP). In April 1971, Stevens made Sierra Leone a republic and he became the first President of Sierra Leone a day after the constitution had been ratified by the Parliament of Sierra Leone.Stevens served as Chairman of the Organization of African Unity (OAU) from 1 July 1980 to 24 June 1981, and engineered the creation of the Mano River Union, a three-country economic federation of Sierra Leone, Liberia and Guinea.Stevens retired from office at the end of his term on 28 November 1985. After pressuring all other potential successors to step aside, he chose Major-General Joseph Saidu Momoh, the commander of the Sierra Leone Armed Forces, as his successor.