100 Escudos of Portugal 1990 CuNi UNC - Astronomical Navigation

Between 1455 and 1485, the conquest of the Atlantic was dominated by Portugal, which led major explorations thanks to advancements in navigation. Under Prince Henry the Navigator’s leadership, the Portuguese discovered the Madeira and Azores islands and explored the West African coast, reaching the mouth of the Congo River. In 1455, the papal bull Romanus Pontifex granted Portugal a monopoly over lands south of Cape Bojador. The 1479 Treaty of Alcáçovas confirmed Portuguese dominance in the Atlantic, marking growing rivalry with Spain before the age of major discoveries.