After abandoning the idea of an Indian origin, today experts agree on the American origin of beans. Both Virgil and Calumella did mention a Phaseolus, but they apparently meant a different legumen of the genus Dolichos, because beans were never found in archaeological findings from the Mediterranean area. On the other hand, remains of beans dating over 7,000 years were found in the excavations of ancient Mexican and Guatemalan cities. And yet beans did not originate in that area either. While Mexico and Guatemala abound in wild forms of this legumen, they are probably only an area of diversification. The area of origin of the bean is now considered to be South America (Peru and Columbia).
Beans were first introduced into Europe by the Spanish conquistadors. In Italy, they were known to be widely grown in vegetable gardens as early as 1569. From Europe, beans later spread to India, Africa, Indochina, and the rest of the world. Today, they are a major crop thanks to their nutritional properties and particularly as a good protein and energy source.
(From Il Divulgatore)