Overseas Discoveries and Conquests

 
When Dom João was proclaimed King of Portugal, a new dynasty, the House of Aviz, began. The coins struck in that period depicted the cross of the Order of Aviz.
In 1415 the conquest of Ceuta triggered a cycle of expansion, which continued down the African coast, culminating in the discovery of the sea routes to India, America and the Far East.

The oriental trade of spices, porcelain and luxury goods flourished with the overseas expansion and Portugal gained access to gold and silver from other sources.

Lisbon became an important trade hub and the main European banking houses established branches in this capital city. At the same time, some Portuguese merchants were already engaged in important financial operations in various international markets. During the reign of King Dom João I copper was introduced in the manufacture of coins – the real preto – and King Dom Duarte adopted the real branco, a coin of a silver-copper alloy (the so-called bolhão), as the new currency unit.
 
King Dom Afonso V, who coveted the throne of Castile, ordered the minting of coins in Toro.

A long period of gold coin production began with the reign of King Dom João II. They were of rare beauty and weight, bearing the characteristic symbols of the overseas discoveries.

These coins, the most important of which was the português of King Dom Manuel I and King Dom João III, acquired international prestige and were widely used. They even influenced the iconography of the gold coins (portugalösers) minted in the 16th and 17th centuries in Northern Europe.