Women sit under the shade of a large tree on a dry riverbed at a makeshift camp for internally displaced people near Seleah village in Sudan's West Darfur province in 2004. At the time, the camp was home to thousands of Sudanese who fled their towns and villages. (Ben Curtis/Associated Press)

Sudan was a collection of independent kingdoms and principalities until 1820 when Egypt conquered the region and united the disparate territories. Egypt held the area until a revolt in 1885. A religious leader, Muhammad ibn Abdalla, led his followers in a nationalist uprising. His people, called the Mahdi ("expected ones") ruled until 1898 when a joint British/Egyptian force overwhelmed the Mahdists.

Sudan was under British/Egyptian administration until 1953 when the UK and Egypt agreed to provide for Sudanese self-government. Sudan became independent on Jan. 1, 1956. The country was never to experience long-term peace. The government in the capital of Khartoum was Arab-led and reneged on promises to southerners, leading to a mutiny by southern army officers. This triggered a 17-year civil war from 1955 to 1972. The war would re-start in the 1980s and continue through the '90s.

Here is a timeline of events from Sudan's independence:

1958

Chief of Staff Lt.-Gen. Ibrahim Abboud overthrows the government of Prime Minister Ismail al-Azhari in a bloodless coup.

1964

A wave of riots against the authoritarian rule of Abboud forces the military to relinquish power. Parliamentary elections are held in April 1965.

1965-1969

A coalition government is formed between the Umma and National Unionist Parties under Prime Minister Muhammad Ahmad Mahjoub. The government is unable to unite the country as it falls into factional fighting, economic stagnation and ethnic skirmishes.

May 25, 1969

A second military coup is staged by Col. Gaafar Muhammad Nimeiri, who becomes the country's new leader. He abolishes parliament and outlaws all political parties. He installs himself as president. Nimeiri briefly loses power in July 1971 to the Communist Party, but his rule is restored within days.

1972

An agreement leads to a 10-year hiatus in the north-south civil war.

1983

President Nimeiri institutes traditional Islamic law (Shariah). He also declares a state of emergency to make sure Shariah is applied widely. Emergency courts are established. Punishments ranging from amputations for theft to public lashings for alcohol possession become commonplace. Nimeiri announces the end of the state of emergency in September 1984. He dismantles the emergency courts and institutes a new judiciary act that continues the practice of Shariah law. Nimeiri's actions spur the Sudan People's Liberation Movement (SPLM) in the south to re-start its revolt.

April 1985

Senior military officers mount a coup and suspend the constitution. They establish a military council to run the country. Soon, the council appoints an interim cabinet led by Dr. Al Gizouli Defalla.

April 1986

Elections are held and the new coalition government is led by Sadiq al-Mahdi of the Umma Party. Over the next few years, the coalition would dissolve and reform several times, but always with the Umma Party in charge. Meanwhile, the civil war intensifies.

February 1989

Al-Mahdi approves an agreement with the SPLM. But, on June 30, military officers take over the government under then-Col. Omar Hassan al-Bashir. The move is supported by the National Islamic Front party. The colonel installs a Revolutionary Command Council supported by a civilian cabinet. Al-Bashir becomes president and chief of the armed forces. Fighting between the SPLM and the government continues.

1991 to 1993

The government institutes a new penal code with harsh punishments, non-Muslim judges from the south are transferred to the north. Muslim judges are installed.

1990s

Conditions deteriorate as the SPLM and government troops continue to clash. Four million people are displaced by the fighting; many face starvation. Meanwhile, the SPLM joins forces with the "National Democratic Alliance" (NDA) and starts an insurgency in the eastern Sudan and northern Blue Nile areas.

1997

The government signs a series of agreements with rebel factions, except the SPLM. Many rebel leaders become part of the government.

2002

The government and the SPLM reach a historic agreement on the roles of the state and religion and the right of southern Sudan to self-determination. It's called the Machakos Protocol, after the town in Kenya where peace talks were held. Both sides sign an understanding for a cessation of hostilities. Discussions continue in 2004 over wealth sharing and some contested areas.

2003

A new rebellion starts up in the western Darfur region bordering on Chad. Residents are mostly black and accuse the government of ignoring the development of the region. Government installations are attacked. Soon, Arab militias – allegedly with air support from the Sudanese government – start attacking villages. The Janjaweed Arab militias are accused of forcing hundreds of thousands of farmers to leave the area. There are reports of rapes and indiscriminate killings. More than 150,000 refugees from Darfur are now living in Chad.

2004

The United Nations calls Darfur the "worst humanitarian crisis" in the world. Governments from around the world pressure the Sudanese government to disarm the Arab militias. Several ceasefire agreements between the government and the rebels – the Sudan Liberation Army (SLA) and the Justice and Equality Movement (JEM) – are broken. Aid groups and the U.S. Congress accuse the Khartoum government of genocide against the black population of Darfur.

2005

Neighbouring Chad declares itself to be in "a state of war" with Sudan. The Chadian government blames Sudanese rebels for an attack on the border town of Adre that killed 100 people.

2006

Sudan is declared the world's most vulnerable state on a ranking produced by Foreign Policy magazine and the Washington-based Fund for Peace think tank.

2007

The UN Human Rights Council accuses Sudan's security forces of "indiscriminately" killing more than 100 people in large-scale attacks in southern Darfur since January.

Amnesty International says it has photographs that prove the Sudanese government continues to deploy military equipment in Darfur in "breathtaking defiance" of a UN arms embargo.

Nuala Lawlor, the acting chargé d'affaires for Canada in Sudan, and her European Union counterpart are expelled from Sudan. No reason is given, though Sudan's official news agency reported that government officials believed Lawlor had been meddling in Sudan's internal affairs.

One week later, Canada expels a Sudanese diplomat as a response to Lawlor's expulsion.

2008

UN reports death toll of 300,000 after five years of conflict. John Holmes, a UN official for humanitarian affairs, released the estimate at a Security Council meeting.

In July, the prosecutor of The Hague's International Criminal Court files genocide charges against Sudan's president, Omar al-Bashir, alleging he orchestrated the violence that has devastated Darfur and left hundreds of thousands dead.

Sources: U.S. Department of State, Wikipedia, Arab Net, CIA World Factbook.