Between the 13th and 15th Centuries, Porto’s shipyards were among the most important in the country, as the city’s commercial and maritime activities underwent great development. Porto strengthened its connections with the major European ports of London, Valencia, Barcelona and Antwerp, and the Portuguese fleet became one of the most powerful in the world.

Navigator Prince Infante D. Henrique was born in Porto in 1394 and ushered in the era of exploration, during which the Portuguese made important overseas discoveries. The inhabitants of Porto are referred to as tripeiros (tripe-eaters) because of a peculiar event that occurred in 1415, when Porto’s army set out to conquer the Muslim port of Ceuta, in Morocco. They gave the soldiers all the good meat and kept only tripe for themselves. Today, ‘Porto-style tripe’ is a traditional dish in the city.
 
The conquest led to the exploratory expeditions down the African coast, by Henry the Navigator. Between 1580 and 1640, Porto was occupied by Spain, when great urban and administrative developments had taken place. This period also witnessed a burgeoning cultural scene, which reached its zenith in the 1700s.

Wine production in the Douro valley was being transported to Porto in the 13th Century. As part of the War of the Spanish Succession, trade relations between Portugal and England were officially established under the Methuen Treaty in 1703, which affected commerce and military operations. Portugal was forced to cease manufacturing developments and transferred its profitable Brazilian gold production to England. Some historians maintain that Portugal lost the industrial race because of this treaty. However, Portugal did emerge as a major political player, which helped it maintain authority over its colony in Brazil.  

Under the treaty, English woolens were imported free of duty, and duty on Portuguese wines exported to England was a third of that levied on French wines. When the war between England and France broke out, it became difficult to obtain wine, which is why ‘port’ became a popular replacement. The first English trading post in Porto opened in 1717, when port wine production was transferred to English companies. The prime minister of Portugal granted a monopoly on wines produced in the Douro valley to a Portuguese company, with the aim to counter English domination, which was the first attempt to control wine production and its quality in Europe. The prime minister provoked the small wine growers by enforcing strict policies, who in turn incited the Revolta dos Borrachos (revolt of the drunks) on Shrove Tuesday, just before Ash Wednesday, burning down the company buildings.