In the second episode of this six-part series, Al Jazeera looks at the events that led to the PLO's expulsion from Jordan and the birth of the Black September Organisation.
The Palestinians took full advantage of the state of chaos that followed Arab defeat in the 1967 Six-Day war.
Palestinian guerrilla factions consolidated their grip on the refugee camps in Arab states and hundreds of fresh recruits swelled their ranks.
The image of the young fedayeen - or freedom fighters - clad in the traditional Palestinian headscarf became an icon of resistance.
While some Arab regimes vied for influence among the Palestinians as a way of gaining leverage on the regional scene, not all held the Palestinians in such high esteem.
In Jordan, armed Palestinians strolled through the streets - enjoying freedom of movement and launching operations from Jordanian territory against Israel.
A bloody showdown was on the horizon - not with Israel, but with fellow Arabs.
Black September can be seen from Monday, July 20, at the following times GMT: Monday: 0530, 1130; Tuesday: 0130, 1400, 2330; Wednesday: 0630, 1630; Thursday: 0300, 1430; Friday: 0600; Saturday: 1930; Sunday: 1030.
Source: Al Jazeera