Hosni Mubarak became the President of Egypt following the assassination of Anwar Sadat on 6 October 1981; this was subsequently legitimized a few weeks later through a referendum in the People's Assembly, the lower house of Egypt's bicameral legislature. He had previously served as Vice President since 1975, a position he gained after rising through the ranks of the Egyptian Air Force during the preceding two decades. He also held the title of Deputy Defence Minister at the time of the 1973 October War.