On its journey across the Iberian peninsula, the Douro River sees hundreds of thousands of grapevines. But while the vines in the Spanish wine-producing districts Ribera del Duero, Rueda and Toro grow on a high plateau composed of clay, gravel, sand and limestone, as soon as you cross the border into Portugal, the vines find themselves coming up out of granite and slate soils. Here during millions of years, the river has etched itself deeply into the earth, on its way to the Atlantic Ocean. The precipitously steep slopes to its left and to its right have been worked by the hand of man over hundreds of years into terraces, which has made agriculture possible. Here the farmers grew grains, potatoes, cabbage and fruits. Moreover, they planted wine grapes in the terrace walls, and in this way used the terraces both vertically and horizontally.

Over the course of the last two hundred years the Douro has been made navigable, and the railroad has laid its tracks down along the river valley; these factors made it possible for the quintas—as these local estates are known—to quite handily transport their production to Oporto and thence to the export markets. Since the 18th century the Douro Valley has developed from a mixed-agricultural territory (as it was in the Middle Ages) to a purely viticultural region. From that point, port wine became the most important if not the sole source of income for the valley's inhabitants. They delivered their grapes or their wines to the port shippers in Oporto, which led to the development of an intimate mutual dependency. It was not until Portugal became a member of the European Union that the longstanding export-monopoly of the large port houses was abolished, and the individual quintas were granted the right to sell directly on the world market.

In the spirit of optimism which has prevailed since then, the five Douro Boys were—and remain—the driving force behind this pursuit of quality, as well as setting the tone for its image.

And if the Douro Valley has in the past ten years become a great discovery of the wine-journalists world-wide, an insider tip from the sommeliers, and the favourite region of many wine lovers, these developments have first and foremost the Douro Boys and their wines to thank.