From the want of any accurate history of the progress of the Portuguese discoveries, it is utterly impossible to determine the dates or circumstances of many of the progressive discoveries along the western coast of Africa, and of its islands. In 1469, Alphonzo farmed the Guinea trade for five years to Fernando Gomez, for the yearly rent of 500 ducats, or about 138 pounds; taking, him bound at the same time, to extend the discoveries for 500 leagues to the southwards during the period of his exclusive privilege. In 1471, according to Marmol, Juan de Santareu and Pedro de Escobar, discovered the Oro de la Mina, or the Gold coast; and advancing still farther, under the guidance of two experienced pilots, Martin Fernandez and Alvaro Esteves, they discovered Cabo Catalina, or Cape St Catherine, in lat. 1 deg. 40’ S. This promontory, which is thirty-one leagues to the south of Cabo de Lope Gonzales, derived its name from the day of the saint on which it was first seen, and forms the northern boundary of the great kingdom of Congo. The discovery of this cape is assigned by some writers to Sequiera, a knight belonging to the royal household.
The celebrated Portuguese historian, Emanuel de Faria, in his Asia Portuguesa, has recorded all the Portuguese voyages, from their first attempts under Don Henry, to their developement of China and Japan, and has even left an account of all the ships that sailed from Lisbon for Africa and Asia, down to the year 1600; but was unable to ascertain the dates of many important events. Neither he nor De Barros have been able to remove the uncertainty respecting the first discovery of the island of St Thomas on the coast of Africa, the south end of which touches the equinoctial. During the remainder of the reign of Alphonzo, the line of coast, from Cape Verga