Also referred to as the (First) Lebanon War, the Lebanon Invasion or Operation Peace in the Galilee. In June 1982, Israel invaded Lebanon purportedly in retaliation for the attempted assassination of the Israeli Ambassador to England by men connected to the Palestine Liberation Organization (PLO). However, Israeli Defense Minister Ariel Sharon had also been seeking a pretext to eliminate the PLO from Lebanon. Despite original statements that Israeli troops would only advance 40 km, Israeli forces quickly reached Beirut, where they laid siege to the Lebanese capital. International forces led by the United States then facilitated the departure of the PLO from Lebanon to Tunisia. Israel encouraged the election of Bashir Gemayel as Lebanon’s new President in August, but he was soon assassinated, after which his supporters massacred hundreds of Palestinian men, women and children in the Sabra and Shatilla refugee camps. Israeli forces remained to occupy much of southern Lebanon and engaged in a low-level guerilla war with Lebanese Shi'a groups, including Hezbollah. The war inspired protests in Israel and empowered the Israeli peace movement, eventually leading to Prime Minister Menachem Begin’s retirement and withdrawal from politics. In 1985, Israel withdrew to a 12 km security zone in southern Lebanon, where it remained until 2000. See Hartley, Cathy, ed. A Survey of Arab-Israeli Relations, 2nd ed. London and New York: Europa Publications, 2004; Herzog, Chaim. Arab-Israeli Wars. New York: Vintage Books, 2005; Habib, Camille H. The Consequences of Israel's Invasion of Lebanon, 1982: Failure of a Success. Ann Arbor, Michigan: University Microfilms International, 1997; and A Country Study: Israel. December 1988. Library of Congress. 21 July 2011. http://lcweb2.loc.gov/frd/cs/iltoc.html.  http://www.justvision.org/glossary/war-1982