On the accession of John II. to the throne of Portugal in 1481, the discoveries along the coast of Africa were resumed with a new spirit. While infante or hereditary prince, his principal revenue was derived from the profits of the Guinea trade, and of the importation of gold from the haven of Mina; and among the first measures of his reign, he turned his attention to the improvement and extension of that valuable branch of commerce. For this purpose, he gave orders to make all necessary preparations for building a fortress and church at the port of Mina. All the requisite materials, even to stones and tiles, were accordingly shipped from Lisbon in a squadron of ten caravels and two transports, with 500 soldiers and 200 labourers or workmen of various kinds. This expedition was placed under the command of Don Diego d'Azumbuja, an experienced officer, under whom were the following naval captains, Gonзalez da Fonseca, Ruy d'Oliveira, Juan Rodrigues Gante, Juan Alfonso, Diego Rodrigues Inglez, Bartholomew Diaz, Pedro d'Evora, and Gomez Aires. This last was a gentleman belonging to the household of Pedro king of Arragon, all the others being noblemen of the household of King John. Pedro de Cintra and Fernam d'Alfonso commanded the transports, and a small vessel attended the squadron as an advice-boat. This squadron sailed on the 11th December 1481, and reached their destination on the 19th January 1482, at an African village named Aldea, where they found Juan Bernardo, who had previously sailed for the coast in quest of gold.
Bernardo was immediately sent by Azumbuja, to inform Camaranзa, the Negro chief of the district, with the arrival of the Portuguese armament, and to desire a conference, with directions to endeavour to impress that chief with a high sense of the rank and character of the Portuguese officers, and of the irresistible power of the armament now upon his coast. Early next morning, Azambuja landed with all his followers, who were secretly armed, in case of meeting with any hostilities from the natives; and moved forwards in great form to a large tree, not far from the Negro village of Aldea, on a spot which had been chosen as a convenient situation for the intended fortress. A flag, bearing the royal arms of Portugal, was immediately displayed upon the tree, and an altar was placed under the shade of its boughs, at which the whole company united in assisting at the first mass that was celebrated in Guinea, offering up their solemn prayers to God for the speedy conversion of the idolatrous natives, and for the perpetual continuance and prosperity of the church which was to be erected on this spot. The day on which this impressive ceremony was performed being dedicated to St Sebastian, that name was given to the valley on which the tree stood, under which they were now assembled.
Soon after the completion of this religious ceremony, Camaranзa approached with a numerous train. Azambuja, sumptuously dressed, and ornamented by a rich golden collar, prepared to receive the Negro chief, seated on an elevated chair, having all his retinue arranged before him, so as to form an avenue. The Negroes were armed with spears, shields, bows, and arrows, and wore a kind of helmets made of skins, thickly studded with fish teeth, giving them a very martial appearance. The subordinate chiefs were distinguished by chains of gold hanging from their necks, and had various golden ornaments on their heads, and even on their beards. After the exchange of presents, and other tokens of mutual respect and confidence, Azambuja made a speech to Camaranзa, through the mediation of an interpreter, in which he explained the purpose of his embassy and expedition, and used every argument he could think of, to conciliate the friendship of the Negro chief, to make him fully sensible of the power of the king of Portugal, and to reconcile him to the intended permanent establishment upon the toast. Camaranзa listened to the harangue, and the explanation of it by the interpreter, in respectful silence, keeping his eyes steadily fixed on the countenance of Azambuja. After which, casting his eyes for some time on the ground, as if profoundly meditating on what he had heard, he is said to have made the following guarded and judicious answer:
"I am fully sensible of the high honour done me on this occasion by your sovereign. I have always endeavoured to deserve his friendship, by dealing strictly with his subjects, and by constantly exerting myself to procure immediate ladings for their ships. Hitherto the Portuguese, who have visited my country, were meanly dressed, and easily satisfied with the commodities we had to give them; and so far from desiring to remain in the country, were always anxious to complete their cargoes, and to return whence they came. This day I observe a wonderful difference. A great number of persons, richly dressed, are eager for permission to build themselves houses, and to remain among us. But assuredly, persons of such rank, under the guidance of a commander who claims his descent from the God who created the day and the night, would never be able to endure the hardships of our climate, and could not procure in this country those luxuries they have been accustomed to in their own. Those passions which are common to all men, will certainly produce disputes between us; and it were much better that we should continue on the same footing as hitherto, allowing your ships to come and go as they have always done before; in which case, the desire of seeing each other occasionally, and of mutual intercourse in trade, will preserve peace between you and us. The sea and the land, which are always neighbours, are continually at variance, contending for the mastery; the sea always violently endeavouring to subdue the land, which, with equal obstinacy, defends itself against the encroachments of the sea."
The prudential jealousy and distrust displayed on this occasion by Camaranзa, astonished and perplexed the Portuguese commander; and it required the exercise of much address on his part, to prevail upon the Negro chief to allow the fulfilment of his orders, and to prevent the necessity of having recourse to violent measures. When the workmen were making preparations next day to lay the foundations of the intended fortress on the coast, they observed a large rock, which lay very commodious for serving them as a quarry, and accordingly proceeded to work it for that purpose. This happened unfortunately to be venerated by the Negroes as one of their Gods, and they immediately flew to arms in opposition against the sacrilegious violation of the sanctified rock, and many of the workmen were wounded, before the natives could be pacified by numerous presents. At length, after the constant labour of twenty days, the fort began to assume a formidable appearance, and received the name of Fortaleza de San Jorge da Mina, or Fort St George at Mina. In a church constructed within its walls, a solemn mass was appointed to be celebrated annually, in honour of Don Henry, Duke of Viseo, of illustrious memory. Azambuja continued governor of this place during two years and seven months, and was honoured, on his return to Portugal, with particular marks of royal favour. In 1486, King John bestowed on this new establishment all the privileges end immunities of a city.
Impressed with the great advantages that might be derived to his kingdom, through the prosecution of the maritime discoveries in Africa, and more especially by opening a passage by sea to India, of which his hopes were now sanguine, the king of Portugal, who had now added to his titles that of Lord of Guinea, made application to the pope, as universal father and lord of Christendom, for a perpetual grant of all the countries which the Portuguese had already discovered, or should hereafter discover, towards the east, with a strict prohibition against the interference of any European State in that immense field of discovery, commerce, and colonization. The pope conceded this enormous grant, probably without the most distant idea of its extent and importance: not only prohibiting all Christian powers from intruding within those prodigious, yet indefinite bounds, which he had bestowed upon the crown of Portugal, but declaring, that all discoveries that were or might be made in contravention, should belong to Portugal. Hitherto, the Portuguese navigators, in the course of their discoveries along the shores of Western Africa, had been in use to erect wooden crosses, as indications of their respective discoveries. But the king now ordered that they should erect stone crosses, about six feet high, inscribed with, the arms of Portugal, the name of the reigning sovereign, that of the navigator, and the date of the discovery.