reigning monarch, King Hussein of Jordan, and following his quashing of the rebellion in what Arab historians call Black September, the PLO leadership and their troops fled from Jordan to Syria and finally Lebanon, where cross-border violence increased. With headquarters now in Beirut, PLO factions recruited new members from the Palestinian refugee camps. South Lebanon was nicknamed "Fatahland" due to the predominance there of Yasser Arafat's Fatah organization. With its own army operating freely in Lebanon, the PLO had created a state within a state. By 1975, more than 300,000 Palestinian displaced persons lived in Lebanon. In reaction to the 1972 Munich massacre, Israel carried out Operation Spring of Youth. Members of Israel's elite Special Forces landed by boat in Lebanon on 9 April 1973, and with the aid of Israeli intelligence agents, infiltrated the PLO headquarters in Beirut and assassinated several members of its leadership. In 1974 the PLO altered its focus to include political elements, necessary for a dialogue with Israel. Those who insisted on a military solution left to form the Rejectionist Front, and Yassir Arafat took over the PLO leadership role. The Popular Front for the Liberation of Palestine – General Command, which split from the PLO in 1974, carried out the Kiryat Shmona massacre in April of that year. In May 1974, the DFLP crossed again into Israel and carried out the Ma'alot massacre. Lebanese Civil War (1975–1990) The Lebanese Civil War (1975–1990) was a complex conflict in the form of various factions and shifting alliances between and among Lebanese Maronite Catholics, Lebanese Muslims, Palestinian Muslims, Lebanese Druze, and other non-sectarian groups. Governmental power had been allotted among the different religious groups by the National Pact based partially on the results of the 1932 census. Changes in demographics and increased feelings of deprivation by certain ethnic groups, as well as Israeli–Palestinian clashes in the south of the county all contributed to the outbreak of the Lebanese Civil War. Israeli support to Lebanese Forces Beginning in May 1976, Israel supplied the Maronite militias, including the Lebanese Forces, led by Bachir Gemayel, with arms, tanks, and military advisers. The border between Israel and Lebanon was at this time was nicknamed the Good Fence. Fearing loss of commercial access to the port of Beirut, in June 1976 Syria intervened in the civil war to support the Maronite dominated government, and by October had 40,000 troops stationed within Lebanon.