From Wikipedia page for Bruce Lee:
"In 2004, UFC president Dana White credited Bruce Lee as the "father of mixed martial arts".
Here is a quote from Lee showcasing his "vision" of Mixed Martial Arts:
"Unfortunately, now in boxing people are only allowed to punch. In Judo, people are only allowed to throw. I do not despise these kinds of martial arts. What I mean is, we now find rigid forms which create differences among clans, and the world of martial art is shattered as a result."