In the 14th and the 15th centuries, Porto's shipyards contributed to the development of Portuguese shipbuilding. Also from the port of Porto, in 1415, Prince Henry the Navigator (son of John I of Portugal) embarked on the conquest of the Moorish port of Ceuta, in northern Morocco. This expedition by the king and his fleet, which counted among others, Prince Henry, was followed by navigation and exploration along the western coast of Africa, initiating the Portuguese Age of Discovery. The nickname given to the people of Porto began in those days; Portuenses are to this day, colloquially, referred to as tripeiros (English: tripe peoples), referring to this period of history, when higher-quality cuts of meat were shipped from Porto with their sailors, while off-cuts and by-products, such as tripe, were left behind for the citizens of Porto; tripe remains a culturally relevant dish in modern-day Porto.

Photo Por Manuel de Sousa - Obra do próprio, Domínio público, https://commons.wikimedia.org/w/index.php?curid=1499281