Port wine be labelled as "port" or "Porto". In the United States, wines labelled "port" may come from anywhere in the world, while the names "Oporto", "Porto", and "Vinho do Porto" have been recognized as foreign, non-generic names for port wines originating in Portugal. Port is produced from grapes grown and processed in the demarcated Douro region. The wine produced is then fortified by the addition of a neutral grape spirit known as aguardente in order to stop the fermentation, leaving residual sugar in the wine, and to boost the alcohol content. The fortification spirit is sometimes referred to as brandy but
Vinho Verde from Espadeiro and Padeiro grapes. The Romans Seneca the Younger and Pliny the Elder both made reference to vines in the area between the rivers Douro and Minho. A record exists of a winery being donated to the Alpendurada convent in Marco de Canaveses in 870 AD, and the vineyards seem to have expanded over the following centuries, planted by religious orders and encouraged by tax breaks. Wines were mostly produced for domestic consumption, although Vinho Verde may have been exported in the 12th century, to England, Germany, and Flanders. The first definite exports to England are recorded by John