Ever since Indonesia achieved independence in 1949, the Jakarta government has faced a constant battle to keep the nation's 13,000 islands together.
Click on the map below for some of the main areas of conflict.
Central Sulawesi has been the scene of particularly brutal skirmishes between Christians and Muslims in recent years.
The town of Poso has acquired an unenviable reputation for some of the region's worst inter-religious violence.
Hostilities first surfaced in late 1998, and carried on well into 2000. After a period of relative calm, they broke out again in late 2001.
The town of Poso was the focal point for much of the violence
Some analysts claim the violence began when fighting between Christian and Muslim communities in the Moluccan islands spilled over into Sulawesi.
Others say it was a consequence of the influx of Muslim migrants from Java under President Suharto's transmigration programme - which reduced the Christian majority in Poso, and thus their powerful position.
A drunken brawl between Christian and Muslim youths sparked the violence in Poso in December 1998 - leaving hundreds dead and thousands homeless.
Unfounded claims that churches had been burned added to the chaotic atmosphere, and there were rumours of black magic being invoked, further inflaming this very traditional region.
By the time the violence subsided many months later, about 1,000 people had been killed and tens of thousands expelled from Poso and the surrounding villages.
In late November 2001, the fighting flared up once again.
There were reports that the militant Islamic group Laskar Jihad was leading the Muslim side, and a study by the International Crisis Group suggested that another regional militant group, Jemaah Islamiah (JI), was also involved.
SULAWESI: KEY FACTS
Previously known as Celebes, Sulawesi is Indonesia's fourth largest island
80% of the population are Muslim, while 17% are Christian
Christians mainly in the north, influenced by nearby Philippines
A paramilitary organisation calling itself the Red Force emerged to retaliate on behalf of the Christian community.
Both groups were armed with bows and arrows, as well as homemade bombs and firearms.
In an attempt to bring about a long-term solution, the two sides met in December 2001 in government-sponsored peace talks.
The resultant declaration of peace, the Malino Accord, was signed by both sides, and produced a dramatic decline in the violence.
But systematic one-sided attacks - bombings and unexplained killings of mostly non-Muslim victims - have continued.
In October 2003, masked gunmen killed 13 Christian villagers in the Morowali and Poso districts - proving that the inter-religious violence in Sulawesi is far from over.