|Grazing and land rights are key issues for those who live in Abyei [EPA]
The oil-producing region of Abyei on the border between north and south Sudan has been claimed by both sides after the civil war between the two rivals ended in 2005.
Deadly clashes in May 2008 between the Sudanese army and the Sudan People's Liberation Movement, which governs the south, raised fears of a return to war.
Both parties decided to take the matter of the sensitive border to arbitration in The Hague.
What was the dispute about?
The Abyei area is a central region straddling the undefined border between Sudan's mainly Muslim north and the mostly Christian south.
For many years, large parts of the territory have been shared by the Ngok Dinka, part of south Sudan's Dinka tribal group, and the northern Arab Misseriya nomads.
Abyei is currently governed by a joint north-south administration, but residents have been promised a referendum in January 2011 on whether they want to join north or south Sudan.
On the same day, South Sudan as a whole will also vote on whether to split from north Sudan and form an independent country.
Why were the two sides arguing?
Both sides differed over the ownership of Abyei and its boundaries - the south said Abyei covered a much larger area of land than the north was prepared to accept.
Abyei is an oil-rich area which neither side would like to lose.
Both want control of oil installations north of Abyei town, run by the Greater Nile Petroleum Operating Company (GNPOC), a consortium led by CNPC of China, the main oil group operating in the Abyei area.
The north could see any loss compounded if the south, as is widely expected, also chooses secession.
Both sides also want to keep the loyalty of communities that supported them during the civil war - for northerners the Misseriya, for southerners the Ngok Dinka.
Abyei has become an emblem for the south and north after decades of fighting and senior members of the south's SPLM come from the area.
What about the people of Abyei?
Grazing and land rights are the key issues for the Dinka and the Misseriya, as both live in the Abyei region.
Many there feel the competition over resources could be managed through traditional settlements and earlier agreements, if the clash had not been escalated to a national level.
How did the dispute end up in The Hague?
The status and borders of Abyei were among the most sensitive issues left undecided in the 2005 Comprehensive Peace Agreement that ended more than two decades of civil war between north and south Sudan.
Efforts to reach a settlement after 2005 failed and northern and southern forces clashed over Abyei a number of times, forcing tens of thousands of civilians to flee.
Clashes over the area left at least 100 people dead in 2008.
Both sides then referred the issue to an Abyei Arbitration Tribunal in The Hague.
What was The Hague court ruling on?
The tribunal was asked to rule on a technical issue - whether a panel of international experts, set up by the 2005 peace deal, went beyond its mandate when it outlined Abyei's borders.
What did the Hague court finally rule?
On July 22, 2009, the international court redraw the borders.
It reduced the size of Abyei compared with proposals laid out after the 2005 deal and effectively awarded more land and mineral wealth to the north.
It gave the Khartoum government control of the Heglig and Bamboo oilfields, the Nile oil pipeline and the railway town of Meiram.
The north declared the ruling a victory while the south said it was satisfied.
Both the government and the SPLM pledged to abide by the ruling.