It seems that this tree was imported in Europe by Greek colonists from Asia Minor during the Bronze Age and its diffusion, starting from the Roman Empire up to the Middle Ages, is due to the nutritional importance of walnuts, a source of important nutritive elements but also of substances used in natural medicine. In ancient times this tree was associated with the figure of Jupiter and the walnuts were thrown in wedding ceremonies, as is today done with confetti. It is widespread in the countryside as a tree associated with the vine, also because it is believed to keep away harmful insects. 