Lebanon's unhappy existence as a separate state began in 1920 with the breakup of the Turkish Empire. It has rarely since then been at peace or in control of its territory. With its ethnic factions usually at odds, the tiny country - about one-third the size of Maryland - has been a cat's-paw for the rivalries of its neighbors.
Until 1941 Lebanon was administered by France under a League of Nations mandate. Nominally independent since then, it has been partially occupied at various times by Syria, Israel and guerrillas from the Palestine Liberation Organization.
Even the parts of Lebanon controlled by Lebanese are mutually hostile. The 3.5 million Lebanese are mostly Arab, but religiously divided between Christians - mostly Maronite, an Orthodox-rite sect in communion with Roman Catholicism - and Muslims subdivided among Sunnis, Shiites and Druze.
The rights of each of these communities is secured by a National Covenant adopted in 1943 that apportions all public positions among religious communities.
By law, the president must be a Christian - the majority community in 1943. An uprising by Muslims against a Christian government in 1958 prompted President Dwight D. Eisenhower to send U.S. Marines.
By the 1970s, Muslims were the majority and demanding a larger political and economic role. Amending the National Covenant - or conducting a proper census - proved impossible, and the country fell into a civil war lasting on and off from 1975 to 1990.
Its early stages were shockingly bloody - an estimated 60,000 dead in 1975 and 1976. Palestinian units and leftist Muslims fought against Christian militias. Several Arab countries provided political and arms support to the various factions, while Israel aided Christian forces.
At the request of Lebanon's government, Syria entered the fighting with a force of about 15,000 troops to oppose Palestinian groups.
This was a risky strategy for Lebanon, for Syria had at times laid claim to Lebanon as a historically Syrian province, but it succeeded in stopping the large-scale fighting. Syria occupied nearly half the country, controlling the Muslim areas in the north and west.
But Lebanon remained weak and disorganized. Palestinian units operated in the south of the country, mounting terrorist attacks across the Israeli border and lobbing Katyusha rocket shells at Israeli settlements.
Israel struck back in 1978 and supported the creation of a local Lebanese military force, known as the South Lebanon Army, under the command of Maj. Saad Haddad, to police Palestinian activity in the region.
More than border security was at stake. Palestinian terrorists were blowing up buildings and attacking Israelis in Europe and elsewhere.
Israel began escalating attacks against PLO infrastructure in Lebanon, in 1981 bombing its strongholds in the capital, Beirut. The next year, on June 6, it moved to clear the PLO out of Lebanon with a coordinated military operation named Operation Peace for Galilee.
Striking by air, land and sea, Israel drove to Beirut and surrounded it. Israeli and Syrian forces clashed in the Bekaa Valley of central Lebanon; Syrian MiGs proved no match for the Israeli Air Force.
In August, after heavy Israeli bombing, the PLO evacuated West Beirut. But the killing was not over. The newly elected Lebanese president, Bashir Gemayel, a Christian thought to be sympathetic to Israel, was assassinated Sept. 14.
A multinational force, including Americans, was interposed in 1983, and Islamic terrorists responded with bombings at the U.S. Embassy, a military barracks and elsewhere. Some 264 U.S. servicemen and 60 French soldiers, among others, were killed. The multinational force left a few months later.
Israelis forces withdrew by 1985 to a southern "security zone," constituting 10 percent of Lebanon's territory.
About 30,000 Syrian troops remained, but in 1991 a treaty between Syria and Lebanon recognized Lebanon as a separate country for the first time since the two countries gained independence in 1943.
Since then, guerrilla groups - now the Iranian-funded Shiite Hezbollah ("Party of God"), not the PLO - have continued to clash with Israeli forces, which have responded with air raids and tit-for-tat artillery shelling.
The Israelis had hoped to leave the South Lebanon Army as a stabilizing force along the border, but the SLA collapsed, and this morning Israel pulled out its troops. Lebanon remains a power vacuum, and Israel continues to have an unstable neighbor to the north.