History of Port

 
However, the emergence of Port wine as we now know it occurred much later. The first wines known by this name were shipped in the second half of the 17th century. 

In 1386 the Treaty of Windsor had established a close political, military and commercial alliance between England and Portugal. Under the terms of the treaty, each country gave the merchants of the other the right to reside in its territory and trade on equal terms with its own subjects.  Strong and active trading links developed between the two countries and many English merchants settled in Portugal. By the second half of the 15th century a significant amount of Portuguese wine was being exported to England, often in exchange for salt cod known in Portuguese as bacalhau.  
 
The Anglo-Portuguese commercial treaty of 1654 created new opportunities for English and Scottish merchants living in Portugal, allowing them special privileges and preferential customs duties. At that time, the centre of the wine business was not Oporto, as it later became, but the elegant northern coastal town of Viana do Castelo whose situation on the broad estuary of the Lima River made it a reliable natural harbour. The merchants imported commodities such as wool and cotton cloth from England and exported grain, fruit, oil and what was known as ‘red Portugal’, the light, acidic wine produced nearby in the verdant Minho region, particularly around the towns of Melgaço and Monção.