1982 Aug. 21-25: Multinational peacekeeping force, including US Marines, arrives to evacuate Palestinian guerrillas after Israelis capture Beirut. Sept. 1: US offers Mideast peace plan. Sept. 10: Marines leave Lebanon. Sept. 14: Hundreds of Palestinian civilians massacred in refugee camps by Christian militia. Sept. 29: Marines return to Beirut. 1983 April 18: US Embassy in Beirut bombed. May 17: Israeli-Lebanese troop withdrawal accord. Aug. 29: First two Marines killed. Sept. 7-8: First artillery fired by Marines in response to attacks. First US shelling from offshore. Sept. 28-29: Congress authorizes Marines to stay in Lebanon for 18 months. Oct. 23: Bombing of Marine and French compounds in Beirut; 241 Americans killed, 58 French. Dec. 4: Two US Navy jets shot down during attack on Syrian positions. Dec. 14: Reacting to Syrian attacks on US planes, US ships bombard Syrian positions. 1984 Feb. 5: Lebanese Cabinet resigns. Feb. 6: Lebanese opposition captures most of west Beirut. Feb. 7: Reagan orders phased evacuation of Marines to ships offshore. US steps up air and naval defense of Marines and Lebanese Army. Feb. 21: Marines begin withdrawal.