Former United Nations Secretary General Kofi Annan has left Kenya after helping secure a deal between the country's rival political leaders.
Many Kenyans celebrated the power-sharing deal
Mr Annan successfully mediated in talks following the presidential election in December which the opposition said was flawed by vote rigging.
A thousand people have been killed in violence since the poll.
The power-sharing deal gave opposition leader Raila Odinga the post of executive prime minister.
Mr Annan has now gone to neighbouring Uganda before returning to his base in Switzerland.
He has said he will be back in Kenya to monitor progress in efforts to reform Kenya's constitution and institutions.
Air of calm
Mr Annan urged all Kenyans to take part in building a healed and reconciled country, and not leave it to the politicians.
"I would urge all of you to remain engaged," he said in a message to Kenyans on his departure.
"We want Kenya to return to the old Kenya: stable, peaceful, prosperous and welcoming."
"Each and every one of you has a role to play," he added.
Mr Annan arrived in Kenya on 22 January when rival ethnic communities were engaged in horrific acts of blood letting following the disputed election.
He said he would come with no solution to Kenya's problems but to insist that one was found.
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The BBC's Adam Mynott in Nairobi says his arrival immediately injected an air of relative calm and that was reinforced when, two days later, he persuaded President Kibaki and Mr Odinga to meet and shake hands.
A negotiating process was set up and agreements on ways to end the violence and tackle the humanitarian crisis quickly followed.
The talks then stalled and started to lose ground.
The former UN secretary general insisted that negotiations were always going to be a matter of give and take.
Debt of gratitude
But a week ago they hit a crisis point and on Tuesday he suspended discussions between the panel and negotiators because no progress was being made.
He said Mr Kibaki and Mr Odinga had to take responsibility and meet.
Five hours of discussions led to an agreement on power sharing and a path towards a stable future.
Our correspondent says Kenyans owe Kofi Annan and his diplomatic skills a huge debt of gratitude.