TIMELINE: Western Sahara, a 50-year-old dispute

(Reuters) - A third round of negotiations to settle Africa's longest-running territorial dispute resume next week in New York when negotiators from Western Sahara and Morocco sit down for talks.

Here is a chronology of the Western Sahara dispute.

1884 - Spain colonizes Western Sahara.

1957 - Morocco raises centuries-old historical claim to Western Sahara at the United Nations.

1973 - Polisario Front is formed and establishes itself as the sole representative of the Sahrawi people.

June 1975 - Morocco's King Hassan takes the territorial dispute to the World Court in The Hague. The court finds that some tribes had paid allegiance to Moroccan rulers, but rules that people should be allowed to settle the sovereignty issue through self-determination. Spain will organize a referendum.

-- November - King Hassan launches the Green March with 350,000 unarmed Moroccans crossing into the territory. Spain agrees to transfer administration of the territory to Morocco and Mauritania.

-- December - Morocco sends in forces to occupy the territory.

1976 - As Spanish troops withdraw, Polisario guerrillas backed by Algeria and Libya proclaim the Saharan Arab Democratic Republic (SADR) with a government-in-exile based in Algeria.