The Methuen Treaty of 1703 gave Portuguese wine England's market at a third less duty than French, and the Douro's black wines were dosed with brandy to survive the sea voyage — in time, dosed during fermentation, which stopped the yeasts and locked in the sweetness. In 1756 Pombal demarcated the Douro with stone pillars — arguably the world's first regulated appellation.
Port lives two lives: vintage, bottled young from the great years to age in glass for decades; and tawny, faded to nut-brown through long years in wood. Tinta Roriz — Tempranillo under its Douro name — runs with Touriga Nacional in the blend, and the shippers' names are still half English.