The navigators proceeded along a rugged coast to the south of the Bay of Horses, upon which the sea breaks with a terrible noise, and which, on account of being entirely composed of a hilly shore, faced with rocks and small rocky islands, is called Otegado, or the Rocky Place. At about twelve leagues distance from the bay of Cavallos they entered the mouth of a river, where they killed a number of sea wolves or seals, the skins of which they took on board in defect of any other productions of the country; these seals were found on an island at the mouth of this river, on which the mariners are said to have seen at least 5000 asleep on the shore. The voyage was continued to Punta de Gale, forming the western head-land of the Rio de Ouro, immediately under the tropic, where a fishing net was found constructed of twine, made from the inner bark of some tree of the palm tribe, but no natives were met with; and as provisions began to grow scarce, the adventurous mariners were constrained to return into Portugal, after ranging for some time up and down the rocky coast of Otegado, without making any important discovery.

About this period, or perhaps considerably earlier, Don Henry obtained a bull from Pope Martin V. by which the sovereign pontiff made a perpetual donation to the crown of Portugal, of all lands and islands which had been or might be discovered between Cape Bojador and the East Indies, inclusively, and granted a plenary indulgence for the souls of all who might perish in the prosecution of the enterprize, and in achieving the conquest of these extensive regions from the infidel and pagan enemies of Christ and the church. In this measure, the philosophical genius and enlarged political views of Don Henry are plainly evinced; and, undismayed by the obstacles which had so long opposed his grand project of discoveries, and the length of time which had been employed in making so very small progress, he shewed himself to have looked steadily forwards to the full accomplishment of his hopes of discovering the route by sea from Europe to India, around the still unknown shores of Southern Africa. The date of this papal grant does not certainly appear. De Barros and Lafitau are of opinion that it must have been posterior to 1440; Purchas places it in 1441; and de Guyon in 1444. But Martin V. died in 1431; and these writers seem to have confounded the original grant from that pontiff, with subsequent confirmations by his successors Eugenius IV. Nicholas V. and Sextus IV264.

The gradual progress of these discoveries were interrupted for a time by an unsuccessful attempt of Edward I. or Duarte, king of Portugal, to gain possession of Tangier in the kingdom of Fez. But the history of this war, in which the Portuguese arms suffered much misfortune and dishonour, are quite irrelevant to the present subject. The plague likewise, which raged at Lisbon in 1438, contributed to the suspension of the patriotic enterprizes of Don Henry. At length, in 1440, Don Henry resumed his project of maritime discovery, and dispatched two caravels from Sagres, which were forced back by unfavourable weather, apparently without even reaching the coast of Africa.

In 1441, a young officer named Antonio Gonzales made a voyage in a small vessel, with a crew of twenty-one men, to the island where so great a number of sea wolves had been seen in the former voyage of Alphonzo Gonzales Baldaya in 1435. In this voyage Alphonzo Gotterez, a gentleman of the bed-chamber to Don Henry, acted as secretary, and the two adventurers were instructed to endeavour to obtain an account of the country and its inhabitants, and to procure a cargo of the skins of the seals or sea wolves, that the voyage might not be entirely destitute of some commercial advantages. After accomplishing this part of his instructions, Gonzales determined to use his utmost efforts for procuring some of the inhabitants of the country to carry back with him to Sagres. For this purpose, he landed at the beginning of the night with nine associates, and having advanced about ten miles into the interior, discovered a native following a camel. The sudden appearance of the Portuguese rendered the astonished Moor perfectly motionless, and before he could recover from his surprize he was seized by Gotterez. On their return to the shore with their prisoner, they traced some recent footsteps on the sand, which led them in view of about forty natives, who withdrew to an adjoining hill, but the Portuguese secured a female Moor who had strayed from the party. With these two prisoners they returned to their vessel, not choosing to run any unnecessary risk, or to make any needless attack upon the natives, which was contrary to the express orders of Don Henry.

When preparing next morning to set sail on their return to Portugal, another Portuguese ship arrived, which was commanded by Nuno Tristan, a gentleman of the princes household. Encouraged by this reinforcement, a second expedition into the interior was immediately resolved upon, in which Nuno Tristan, Diego de Vigliadores, and Gonzales de Cintra, joined with Alphonzo Gonzales and Alphonzo Gotterez. Advancing again under night, they soon perceived a party of the natives whom they immediately attacked, shouting out Portugal! Portugal! San Jago! San Jago! The Moors were at first stupified with fear and surprise; but recovering from their panic, a struggle ensued, in which three of the Moors were slain, and ten made prisoners, the Portuguese being indebted for their safety to their defensive armour. After endeavouring, in vain, to establish an intercourse with the Moors for the redemption of the prisoners, Alphonzo Gonzales returned to Sagres with a cargo of skins and the Moorish prisoners, and was honourably rewarded by his discerning master. The place of this exploit was named Puerto del Cavallero, or the Knights Harbour, on occasion of Gonzales being there knighted by Nuno Tristan.

After careening his vessel, Nuno Tristan proceeded along the coast according to his orders, and reached a cape in lat. 20° 50' N. to which he gave the name of Cabo Branco, or the White Cape, on account of the whiteness of its cliffs. He there landed and found some fishing nets on the shore; but after repeated incursions into the country, being unable to meet with any of the natives, he made a survey of the coast, and returned to Portugal with an account of his proceedings.

Three of the prisoners carried to Portugal by Gonzales were Moors of some rank and considerable opulence; who each promised to pay ransoms for their safe return to their native country, and to give, besides, six or seven slaves each to the captors. Don Henry, as grand master of the order of Christ, was eager for the acquisition of so many converts from the religion of Mahomet, and was in hopes that the favourable report which the Moors might make on their return to Africa, would induce the natives to enter into trade with his navigators; and that, among the slaves which were to be given in exchange, some certain knowledge might be acquired of the burning regions of Africa, about which such strange reports were then prevalent. Antonio Gonzales was therefore dispatched on another voyage in 1442, accompanied by a German gentleman named Balthazar, who had distinguished himself in the late unfortunate attempt on Tangier, and who was anxious to carry home some account of the newly discovered countries. After being forced to return to port, to repair the damages they had sustained in a dreadful tempest, they again sailed, and reached the coast where the Moors had been made prisoners. The principal Moor was landed, and was received with great deference and respect by his countrymen; but he forgot all his promises on regaining his liberty, and never returned to pay the ransom he had bargained for. It would appear, however, that he had informed the natives of the return of the other two chiefs; as at the end of nine days, above an hundred natives appeared on the coast, and entered into treaty for the ransom of their two countrymen who remained captives, and for whom ten negroes, natives of different parts of Africa, were given in exchange. During these transactions, the sight of a considerable quantity of gold dust in the possession of the Moors, excited the most lively emotions in the Portuguese, as being the first intimation of that valuable commodity being procurable on the coast of their new discoveries. From this circumstance, Gonzales gave the name of Rio del Ouro, or Gold River, to the deep arm of the sea in which he now lay, which penetrates about six leagues N. N. E. from the tropic of Cancer.