BRAZIL had between 2.5 million and 6 million Indians when the Portuguese landed in 1500, historians estimate.
During the colonial era, adventurers known as bandeirantes embarked on expeditions to enslave Indians to work on Portuguese plantations. So many from the Guarani tribe were hunted that Jesuit priests created settlements to protect them. Their plight was dramatized in the 1986 film ''The Mission.''
Today, some 180 tribes and their 300,000 members could fit inside two large Rio soccer stadiums.
In the 20th century, the quest to conquer Indian lands began in earnest during the military dictatorship of 1964-85, when successive regimes opened up Brazil's last great frontier - the Amazon basin, which comprises seven states, and an area of more than 1.3 million square miles, or 42 percent of national territory.
The 1967 Constitution declared all Indian lands as federal territory, giving the government the right to exploit any untapped resources.
Military rulers then embarked on building a road through the jungle expanse. The $1 billion trans-Amazon highway brought cattle ranchers, gold miners, loggers, and poor farmers in a human stampede that one observer wrote was ''perhaps the greatest land rush since the settling of the American West.''
When Indians attacked the intruders, they were sent to reserves for reasons of ''national security'' and ''development.'' These reserves often harbored traditional tribal enemies, creating constant friction.
With Brazil's return to democracy in 1985, a new Constitution was written. While Indian land remained the property of the federal government, the 1988 document recognized the ''original right to the land that they traditionally occupy'' and called for demarcation within five years. By the time the deadline expired in 1993, only about half of the 554 indigenous areas had been marked.
To speed up the process, then-President Fernando Collor de Mello issued presidential Decree 22, giving the National Indian Foundation the freedom to demarcate Indian reserves without legal interference from non-Indians. This year, President Fernando Henrique Cardoso amended Decree 22 with his controversial Decree 1775, allowing non-Indians the right to contest any future demarcation within 90 days.