The true origins of Jiu-Jitsu are impossible to trace.  Elements can be tracked back over 2500 years.

Chikura Kurabe, a wrestling sport that appeared in Japan in 230BC had many techniques that are incorporated into modern Jiu-Jitsu.  In 880AD the first Jiu-Jitsu Ryu was formed by Prince Jeijun.

Jiu-Jitsu is also the father of some fairly new martial art styles.