The Portuguese living at the time in Kongo were placed under a royal factor and a Corregedor (magistrate), and enjoyed ex-territorial jurisdiction. They had a factory at Mpinda, at the mouth of the Kongo, where the King of Portugal levied heavy duties. The commercial relations do not appear to have been at all times of the most friendly nature. In 1514 the King complained that Fernão de Mello, the Governor of S. Thomé, traded with the Mpangu-lungu[326] who were his enemies; and in 1526 he remonstrated against the conduct of the Portuguese slave-merchants. Indeed, so preposterous were the claims put forward by the Portuguese officials, that King Affonso, in 1517, humbly begged to be allowed to employ a ship of his own when trading; or, at least to be exempted from paying the heavy duties exacted by a foreign, albeit suzerain, power upon the outlanders trading in his kingdom. These ill-advised exactions explain, too, why trade gradually deserted the Kongo, and sought more favourable openings to the south, at Luandu, as is shown by an inquiry held in 1548.[327] The Portuguese made an effort to exploit the mineral wealth of the country. Ruy Mendes, the “factor of the copper mines,” is stated to have discovered lead; and Gimdarlach (Durlacher?), a German “fundidor,” in 1593 discovered copper, lead, and silver. The King, however, would not allow the mines to be worked, for he feared that such a concession might cost him his kingdom. Proposals for the exploration of the interior were made, but bore no fruit. Gregòrio de Quadra, who had spent several years as a prisoner among the Arabs, was sent to Kongo in 1520, with instructions to make his way thence to the country of Prester John. The King refused his consent; Quadra returned to Portugal, and died a monk.[328] Balthasar de Castro, the companion of Manuel Pacheco in Angola, desired to explore the upper Kongo in 1526; but neither his scheme nor that of Manuel Pacheco himself, who was to have built two brigantines, seems to have been carried out. Of the domestic wars corned on by the King, we know next to nothing. Angola and Matamba seem to have been virtually independent in his day, though the island of Luandu, with its valuable cowry-fishery, was held by him and his successors until 1649. He conquered, however, Mpanzu-alumbu (Mpangu-lunga?)[329] on the lower Kongo, a district inhabited by a predatory tribe.[330] That his successes in these “wars” were due to his Portuguese mercenaries and their fire-locks is a matter of course. Don Affonso died in 1540, or soon afterwards, leaving behind him a son, D. Pedro, who succeeded him, and three daughters.[331] D. PEDRO AND HIS SUCCESSORS, 1540-1561.