By Andrew Simmons
BBC News, Dakar
Senegal's President Abdoulaye Wade is to sign a peace deal with rebels in the Casamance aimed at resolving a conflict that has lasted more than 20 years.
President Wade (left) in an earlier meeting with Father Diamacoune
He is due to fly to the region's capital, Ziguinchor, on Thursday to agree a ceasefire and open up dialogue between separatists and his government.
The Casamance conflict has killed some 3,500 and displaced tens of thousands.
The treaty is likely to be more of a building-block than an immediate solution to the separatist sentiment.
Its signing could nonetheless herald the most positive step in West Africa's longest-running civil conflict.
Two decades of violence have been followed by two years of relative calm and sporadic dialogue.
Casamance is the south-western corner of Senegal's territory, yet it is physically separated by a legacy of colonial history - the former British colony of The Gambia.
After more than a decade of unrest, it was in 1982 that many of the region's majority Diola people rebelled, claiming they were being marginalised by the Walof people, the largest ethnic group in Senegal.
The Movement of the Democratic Forces of Casamance launched a campaign of violence which has become deeply factionalised, with its fighters spreading across the borders of The Gambia to the north and Guinea-Bissau in the south.
The late 1990s saw the worst levels of violence and it was not until Abdoulaye Wade became Senegal's president in 2000 that any real commitment to resolving the conflict came about.
Now, with full ceremony, the president of Senegal will meet face to face with the twice-jailed leader of the Casamance rebels, Father Diamacoune Senghor.
Father Diamacoune, now aged 77, may still appear as the figurehead of the Casamance movement, but his leadership has been seriously undermined and there are doubts about which factions of the movement's military wing support him.
However, there does appear to be a general consensus now that a ceasefire can hold the only key to progress.
Casamance's white beaches were once a tropical haven for European tourists and its fertile land an important part of Senegal's agricultural output.
A lasting peace would see major international aid packages to rebuild villages, de-mine the countryside and revive tourism, agriculture and the fishing industry.
But the crucial issue will be the disarmament of rebel fighters, many of whom are split into secret groups.
Without success in this, the rebuilding of the Casamance economy has little chance.