But the proceedings on Sunday were somewhat overshadowed by the refusal of one of Sudan's largest opposition parties to participate in the commission which will form the country's new constitution over the next six weeks.
"This interim constitution will form the basis of the most important and historic stage of this nation," President Omar Hassan al-Bashir told ministers, opposition politicians and former southern rebel leaders, many of whom had returned to the capital for the first time in more than two decades.
Sudan's government and the former rebel Sudan People's Liberation Movement (SPLM) ended more than 20 years of civil war in the south with a peace deal in January. The deal provides for a new national unity government and sharing wealth and power.
The two sides hope the constitution will be a translation of the agreement into a legal framework, and have tried to keep control over the 60-seat constitutional commission to ensure this.
Umma Party objection
But they compromised to give more seats to the opposition parties to allow them a say in the formation of the charter.
The commission needs a two-thirds majority to take a decision and the government and SPLM have retained about 63% of the seats.
Islamist Hassan al-Turabi's Popular Congress Party agreed to participate, and the broad-based Democratic Unionist Party said it would probably join in about 10 days after further talks.
"I urge all political parties ... who have not yet joined the process to shed their doubts and inhibitions ... because by so doing ... they will have discharged a sacred national duty and made a historic and invaluable contribution to the shaping of Sudan's political future"
Former SPLM leader
But the popular Umma Party, led by the last democratically elected leader of Sudan, Sadiq al-Mahdi, has refused to join the commission, saying it wants more seats to be given to opposition political forces.
Senior former rebel official Nhial Deng read out a speech on behalf of SPLM leader John Garang, who will return to Khartoum to take up the post of first vice president once a new government is formed.
"I urge all political parties ... who have not yet joined the process to shed their doubts and inhibitions and join the process because by so doing ... they will have discharged a sacred national duty and made a historic and invaluable contribution to the shaping of Sudan's political future," Garang's speech said.
Deng led a minute silence in memory of the more than two million people who lost their lives during the southern civil war, Africa's longest.
More than two million were killed
in Sudan's 20-year civil war
But the delight of politicians and former commanders who had spent decades as bitter enemies burst through as they jumped to their feet, embraced their former foes and danced together to traditional Sudanese music.
Once the new constitution is approved by the parliament and the SPLM's general assembly, a new government will be sworn in. Al-Bashir said the new government should be formed by 9 July.
The southern peace deal does not cover a separate conflict in Sudan's western Darfur region.