Because in the history of colonization, the Portuguese trafficked black slaves from Africa to Brazil, and the samba of these blacks became the samba of Brazil.
In the 16th to 19th centuries, the Portuguese have been sporting black slaves to Brazil for huge profits. According to records, the number of slaves transported to the number of 12 million, has been a very huge number, so it seems logical that the culture of Africa brought to Brazil to spread. Its transportation of black slaves, due to the long distance, the Portuguese fear that the cabin of the black Africans will be on the cabin dozens of days of inactivity, look sickly, so they asked them to dance Samba in the cabin.
Semba dance is Africa with religious nature of the dance, is the black natives first began to jump. This Samba is actually a kind of belly dance, in the process of jumping mainly shaking hips and twisting waist, relatively simple. After the influx of black slaves into Brazil, the dance was learned by women in Bahia and felt so good that it spread to Rio de Janeiro, Bari. The dances learned from the slaves were not so easy to accept, and there were key people and events that made them possible.
The fiery temperament embedded in this dance is loved by Brazilians and is irrepressible despite coming from the culture of the Negroes. From the favelas to the upper classes, from blacks to whites, the dance spread more and more, eventually taking the country by storm. The popularity was marked in 1928 by the appearance in Rio de Janeiro of the first Brazilian school to teach the passionate samba, the name of which stood for the development, "Let there be gossip".
In the process of the development of samba to samba, which also has a rich and changing. What remains unchanged is the passionate and open movement of the shaking body, and what has changed is some of the instruments, the sound, so that the dance is more in line with the habits of the Brazilians themselves.