In ancient Rome the walnut tree was sacred to Jupiter, the name walnuts in fact meaning "acorns of Jupiter." Walnuts, like almonds and chestnuts, have been a valuable food for mountain peoples for years, and for this reason referred to as poor man's bread.
80 percent of the world's almond production comes from California; it was introduced very anciently to Mediterranean regions, where it is now extensively cultivated and used in several traditional cuisines.