Prelude to Portuguese Maritime Exploration

Timeline

1. 1351–1355Portuguese Atlantic coast · PortugalDuring the reign of Peter I, Portugal consolidated royal authority and reformed port tariffs; Atlantic coastal fishing and salt trade prospered, and shipwrights accumulated experience building ocean-going sailing vessels, providing technical and manpower reserves for later expeditionary fleets.
2. 1351–1356Portuguese-Castilian border · IberiaPortugal intervened in Castile's civil war and clashed with Castile repeatedly on land and at sea; military pressure led the crown to prioritize naval construction and coastal defense, while also stimulating the search for overseas trade routes to break free of peninsular limitations.
3. 1356–1360Port of Lisbon · PortugalLisbon became an Atlantic trade hub; chart-making and astronomical navigation knowledge arrived from the Mediterranean via Genoese merchants, and the crown began issuing charters to encourage ocean fishing and coastal voyaging, laying institutional groundwork for Prince Henry's navigational school and African exploration policies in the 15th century.