The day began with shootings near the church in Ain al-Rummaneh, where Pierre Gemayel was attending a consecration; his bodyguard Joseph Bou Assi was killed. In the early afternoon Kataeb militiamen fired on a bus returning to Tal al-Za'tar from a rally of the Arab Liberation Front. Most historians count 27 dead (Hanf, Fisk, de Clerck and Malsagne: 27 of 35 passengers); Traboulsi gives 21 and Ménargues 31. According to de Clerck and Malsagne the bus carried Palestinians and Lebanese in equal numbers, all men. Fighting spread that evening across the suburbs of Beirut.

After several days of fighting (Hanf; four, says Traboulsi), Pierre Gemayel gave up to the police two militiamen implicated in the Ain al-Rummaneh shooting. Early Syrian mediation failed to stop this round, which de Clerck and Malsagne end with a cease-fire on 16 May 1975; no book confirms a truce on 15 April.

De Clerck and Malsagne and Tegho Bou Nassif date Zahleh's entry into the war to 24 August 1975, when Palestinian fighters planted a bomb in its tourist district, Wadi al-Arayish. In Hanf's account, Zahleh's Christians and Shi'is of its outskirts and nearby villages, helped by Palestinian guerrillas, came to blows late in August after a non-political arcade quarrel. Three Zahleh men were executed at the end of August.

Parliament used the truce to amend Article 73 of the constitution so that Frangieh's successor could be elected early: on 9 April according to Hanf, 10 April according to Yara El Khoury. The truce had coincided with the arrival on 31 March of the US envoy Dean Brown.

Traboulsi's chronology puts the Syrian-PLO accord to restore order in Beirut on 11 April. Around 9 April Syrian army tanks entered the Bekaa at Anjar, Judaydat Yabus and Bayadir al-Adas (Traboulsi), some forty in all according to Yara El Khoury, as Saiqa fighters set about ending the siege of Zahleh.

Historians date the entry of Syrian regular troops to 1 June 1976 (Ménargues gives 9 June). President Assad announced it in the presence of the visiting Soviet Prime Minister Kosygin, citing appeals from the Akkar villages of Qubayat and Andaqit, besieged since January and attacked by the Lebanese Arab Army on 27 May. Columns moved towards Akkar and Tripoli, Zahleh and the Bekaa, and Sidon by way of Jezzine. Estimates of the force range from 6,000 men at the start (with 260 armoured vehicles, according to Ménargues) to 12,000-15,000 within weeks, with 250-300 tanks (de Clerck and Malsagne).

In Beirut in early June, Hanf writes, Fatah and its allies turned on Saiqa, the PLA and the pro-Syrian parties and cleared them from the city within a few hours. Syria's regular army stayed outside the capital for now: on 7 June its troops got as far as Sofar on the Beirut-Damascus road and into Sidon, where an armoured column was wiped out. Syrian forces reached Beirut only in mid-November, within the Arab Deterrent Force.

Picard (2016) dates to 9 June 1976 the Arab League Council resolution, taken in Cairo, that created an Arab peace force. Hanf has some 2,000 Sudanese arriving first, then Libyans; Picard (2002) says Tripoli sent 500 men in June.

Fisk reports that the bodies of Ambassador Francis Meloy, his economic counsellor Robert Waring and their Lebanese driver, abducted near the Museum crossing, were found that evening at Ramlet al-Baida, and that Arafat, once sure of the three Palestinians responsible, sent them to Tyre. De Clerck and Malsagne judge that the murders ended American efforts at a settlement through the Lebanese parties.

Barely a tenth of American and British residents accepted the evacuation, Fisk writes. The British went by road, the PLO escorting them through West Beirut and a Libyan officer on to the Syrian lines; a day later a US landing craft took evacuees off from a PLO-guarded bathing club on the Corniche.

Sudan supplied the Arab peace force's first contingent, some 2,000 men, and Libya the next (Hanf).

Yara El Khoury dates the start of the final offensive on Jisr al-Basha and Tal al-Za'tar to 22 June 1976, and Hanf's account (Jisr al-Basha stormed eight days after the first assault, on 1 July) points to the same week. The camps had been blockaded since January. Hanf says Chamoun's Tigers and Christian units of the army led the attack, the Kataeb joining later; a joint command of Bashir Gemayel (Kataeb), Dany Chamoun and Nabil Karam (NLP), Fawzi Mahfouz (Tanzim) and Etienne Saqr (Guardians of the Cedar) coordinated it (de Clerck and Malsagne).

Tal al-Za'tar fell on 12 August 1976 (13 August in Ménargues) after more than 70 assaults. Ménargues and Hanf count a siege of 52-53 days from the final offensive; de Clerck and Malsagne and Traboulsi count six months from the January blockade. An ICRC report cited by de Clerck and Malsagne puts the dead at about 2,500 residents and defenders and up to 800 attackers; many died trying to escape. The Tigers and the Guardians of the Cedar led the last assault, reportedly with Syrian and Israeli officers present. The camp was bulldozed and never rebuilt.

Hanf has the Syrian army moving again only once Tal al-Za'tar had fallen, increasing pressure on the encircled Palestinian and leftist forces in the Upper Metn; these were expelled at the end of September.

Sami al-Khatib took over the ADF from Ahmad al-Hajj, who never won Syria's trust, and led it until 1983.

Vance's airport motorcade skirted Sabra and Chatila after a Beirut visit, dated by Fisk to autumn 1977, to hear the government's views on the Palestinians' future.

Hanf records that Damascus rejected the Lebanese Front's demands of May 1977: annulment of the Cairo Agreement and dispersal among other Arab states of the 200,000 Palestinians its leaders regarded as illegal entrants.

By now Syria was fighting on the Palestinians' side. Hanf says the clashes ended once the Arab Deterrent Force's Saudi and Sudanese contingents deployed between Chiyah and Ain el-Remmaneh.

Neither parliament nor president could enforce the resolution, Hanf notes. The 74 deputies in attendance passed it without dissent: it reserved arms to the legitimate Lebanese forces, told the Palestinians and 'other parties' to end armed action, and applied Lebanese law to all on Lebanese soil.