[citation needed] Member State of the Arab League The Sudan Tribune claims that the Dajo people were located in the region of Abyei prior to the seventeenth century, before being displaced by new migrants.

The reason was threefold: to protect the Ngok Dinka from raids by the Messiria and thus pacify the area; to demonstrate that a new sovereign power was in control; and to bring the two feuding tribes under common administration.

[10] The two peoples began to take separate paths with the onset of the First Sudanese Civil War (1956–1972), in particular the 1965 massacre of 72 Ngok Dinka in the Misseriya town of Babanusa.

The 1972 Addis Ababa Agreement that ended the war included a clause that provided for a referendum allowing Abyei to choose to remain in the north or join the autonomous South.

Partially as a result of their early entry into the war, many Ngok Dinka rose to leadership positions in the Sudan People’s Liberation Army (SPLA), becoming closely associated with John Garang.

[12] By the end of the war the intense fighting had displaced most Ngok Dinka out of Abyei, which the Misseriya state as justification for ownership of the area.

The SPLA negotiators then spent several years attempting to give these regions the right to a referendum in which they could decide if they want to be under the administrative control of the north or south.

[4] The ABC presented their report to the president on 14 July 2005, whereupon it was immediately rejected by the government, who accused the experts of using sources after 1905 in their determination of the boundaries.

The death of John Garang later that month pushed all other issues off the national agenda, but the SPLA maintains that the terms of the Abyei protocol must be held to.

These grievances fed into armed clashes in December 2007, which killed at least 75 people, and further violence in February and March 2008, resulting in numerous deaths and civilian displacement.

[19][20][21][22][23][24] The Messiria were not believed to be directly controlled by Khartoum, however analysts pointed out that local disputes over resources are readily manipulated by outside forces.

[31] Following the clashes in Abyei during May 2008, in June 2008 the Sudanese President, Omar al-Bashir, and the President of the autonomous Government of Southern Sudan, Salva Kiir Mayardit, agreed to refer the disputes between the Government and the SPLM/A concerning the ABC's determination of the Abyei area's boundaries to international arbitration at the Permanent Court of Arbitration (PCA), in The Hague.

[33] The SPLM/A appointed Dr. Riek Machar Teny, Deputy Chairman of the Sudan People's Liberation Movement and Minister Luka Biong Deng, as Agents, and Gary Born, Paul Williams and Wendy Miles as counsel.

Following extensive written pleadings,[34] in April 2009 the parties presented their closing submissions to the arbitration tribunal over six days at an oral hearing at the Peace Palace, The Hague.

[35] Following the hearing the arbitral tribunal then began its deliberations and, less than ninety days later, on 22 July 2009 rendered its final binding decision as to the validity of the boundaries for Abyei and the ABC had drawn.

The size of Abyei is crucial to the political dispute, as its residents will be able to vote in a referendum on whether to become part of northern or southern Sudan.

[39] While the Dinka Ngok and Messiria tribe maintained a peaceful coexistence during the civil war, the division of Sudan has created mistrust between the two people.

Labor leader Abraham Sebit, leading the protest in Malakal, Upper Nile, asked for intervention by the United Nations and suggested a no-fly zone could be established over Abyei.

[48] The United Nations Interim Security Force for Abyei, consisting of Ethiopian troops commanded by Lieutenant General Tadesse Werede Tesfay, were to be deployed under a UNSC resolution from 27 June 2011.

[49] The peacekeepers began arriving in Abyei on 15 July 2011 after traveling overland from Ethiopia, just under a week after South Sudan formally declared its independence.