Rise of the Portuguese Kingdom

In 1094 Alfonso VI of León and Castile made Portugal, from the Minho River to Coimbra, a separate county under the rule of his son-in-law, Henry of Burgundy. Alfonso (I) Henriques, Henry's son, took the title of king in 1139. He extended the kingdom south to the Tagus River, and made Coimbra the capital. By the mid-13th century the southern boundary was the coast, and Lisbon became the capital.

Castile made repeated attempts to regain Portugal. When this goal was achieved finally by marriage, the half-brother of the previous ruler led a revolt, defeated the Castilian forces at Aljubarrota in 1385, and took the throne as John I of the House of Aviz. The Treaty of Windsor, 1386, established a permanent alliance between Portugal and England.

Under the Aviz dynasty Portugal underwent its period of greatest achievement. Prince Henry the Navigator, a son of John I, started the search for a route to the Indies. Bartholomeu Dias rounded the Cape of Good Hope in 1488, and Vasco da Gama reached India in 1498. Pope Alexander VI in 1493–94 established the Line of Demarcation, dividing the world's unclaimed lands between Spain and Portugal. Pedro Alvares Cabral reached Brazil and claimed it for Portugal. Trading stations were established in Morocco and on the west and east coasts of Africa, as well as in India. Colonial trade brought wealth and power to the nation.