Before Mubarak took command of the Egyptian government, the third President of Egypt, Anwar Sadat, had been in office since 1970. President Sadat had significantly changed the course of Egypt, reinstating a multi-party system and allowing for an increase in foreign investment, among other measures. Also, during Sadat's presidency Egypt both fought in the Yom Kippur War against Israel and, five years later, successfully negotiated the Camp David Accords; this allowed the country to regain sovereignty over the Sinai Peninsula that Israel had been in control of since 1967. Because of these negotiations and their outcome, both he and Israeli Prime Minister Menachem Begin were awarded the Nobel Peace Prize in 1978, which made Sadat the first Muslim Nobel laureate. On 6 October 1981, President Sadat was assassinated in Cairo during the annual celebrations of Operation Badr by members of Egyptian Islamic Jihad, an Islamist terrorist group. About a week after Sadat's assassination, then Vice-President Hosni Mubarak took office as president, an action that was approved through a referendum of the People's Assembly.