During the age of exploration, Spanish and Portuguese captains and "conquistadores" were careful to always set aside the royal fifth from any spoils they captured, and accusations of embezzling the 'royal fifth' ended the careers of a few of them (e.g. Alonso de Ojeda, Pedro Alonso Niño). Nonetheless, to encourage exploration and colonization, Iberian monarchs often allowed explorers and colonial developers to retain part or all of the royal fifth, for at least some period of time. The conditions were usually spelled out in captaincy contracts or royal grants, e.g. in 1402, Jean de Béthencourt was allowed to keep the royal fifth as a condition for the conquest of the Canary Island for Castile; in 1443, the Portuguese Prince Henry the Navigator was granted the royal fifth on all enterprise in the Madeira islands and sub-saharan Africa; in 1492, Christopher Columbus was allowed to retain 10% of the royal fifth of the West Indies (although he famously argued he was promised more); the 1532 contracts of the captains-donatary of colonial Brazil allowed them to retain 5% of the royal fifth. In Spain, the quinto real on mining of all precious metals and minerals (in theory; in practice, it was collected only on gold, silver, mercury, gemstones and pearls) was codified by the edict of February 1504, and (with occasional exceptional grants) remained in force through all the Spanish empire until the 18th century. In 1723, it was reduced to a "diezmo" (10%) and in 1777 it was reduced further to 3%, with an additional duty of 2% if shipped to Spain.