Was Vipassana discovered by the Buddha (Siddhartha)?

I read somewhere that *samatha* (and jhana) was discovered by the Buddha, but how about *vipassana*? Is there any evidence either way (i.e. suttas)? The reason I'm asking is because I am more proficient at practicing *vipassana* meditation than *samatha*, but I have some doubt about *vipassana* itself. Perhaps, if there were some proof that this method was founded by the Buddha himself, my doubt would be gone. Note: I would prefer answers based on Theravada suttas.