The modern real was introduced in 1994, when it replaced the old currency, the cruzeiro real, as part of the Plano Real, a substantial monetary reform package that aimed to put an end to three decades of rampant inflation.

At the time it was meant to have approximately fixed 1:1 exchange rate with the United States dollar. It suffered a sudden devaluation to a rate of about 2:1 in 1999, reached almost 4:1 in 2002, then partly recovered and has been approximately 2:1 since 2006. The exchange rate as of September 2015 is BRL 4.05 to USD 1.00.

Source: Wikipedia