Who painted the world famous farmer and his wife?

Everybody and their stepmom knows DaVinci painted the Mona Lisa. Most people are aware Michelangelo pointed the Sistine Chapel, Venus De Milo, and the Last Supper. Anyway, I'm curious to know who it was that painted the farmer and his wife. I see several depictions of that mural in more places than I care to remember. I even recall seeing Paul Newman and his wife portrayed upon his health food products at the health food store. So who was it that painted the original picture?