The art began when the Japanese Judoka (judo practitioner) Mitsuyo Maeda left Japan on assignment from the Kodokan (judo’s home) to teach Judo the world.

He arrived in Brazil in 1914 and met an influential businessman in Gastão Gracie, who helped him establish himself there.

In return Maeda taught Judo to Gastão’s 14 year old son Carlos.

Carlos went on to practice and teach the art in Rio de Janeiro.

His brother Hélio (to young and debilitated by his health to practice Jiu-Jitsu) learnt by watching his brother practice the art.

After over coming his sickness Hélio went on to teach and refine the art that would become know as Jiu-Jitsu, utilising more leverage and adding more precision to the positions

and developing a more methodical form of ground fighting.

http://en.wikipedia.org/wiki/Bjj