“The account which João de Barros has transmitted to us of the remarkable expedition which resulted in the discovery of the Cape of Good Hope is fragmentary, and on some points undoubtedly erroneous. Unfortunately, up till now no official report of the expedition has been discovered; but there are a few incidental references to it, which enable us to amplify, and in some measure to correct, the version put forward by the great Portuguese historian.
“Most important among these independent witnesses is a marginal note on fol. 13 of a copy of Pierre d’Ailly’s Imago mundi, which was the property of Christopher Columbus, and is still in the Columbine Library at Seville. This ‘note’ reads as follows:—
“‘Note, that in December of this year, 1488, there landed at Lisbon Bartholomeu Didacus [Dias], the commander of three caravels, whom the King of Portugal had sent to Guinea to seek out the land, and who reported that he had sailed 600 leagues beyond the furthest reached hitherto, that is, 450 leagues to the south and then 150 leagues to the north, as far as a cape named by him the Cape of Good Hope, which cape we judge to be in Agisimba, its latitude, as determined by the astrolabe, being 45° S., and its distance from Lisbon 3100 leagues. This voyage he [Dias] had depicted and described from league to league upon a chart, so that he might show it to the king; at all of which I was present (in quibus omnibus interfui).’
“The same voyage is referred to in a second ‘note’ discovered in the margin of the Historia rerum ubique gestarum of Pope Pius II., printed at Venice in 1477. From this second note we learn that ‘one of the captains whom the most serene King of Portugal sent forth to seek out the land in Guinea brought back word in 1488 that he had sailed 45° beyond the equinoctial line.’
“Las Casas (Historia de las Indias, lib. i. c. 7) assumed these notes to have been written by Bartholomew Columbus, whom, as the result of a misconception of the meaning of the concluding words of the note, he supposed to have taken part in this voyage. These assumptions, however, are absolutely inadmissible, for as early as February 10, 1488, Bartholomew had completed at London a map of the world for Henry VII. If we remember that Bartholomew was detained by pirates for several weeks before he reached England, he must have left Lisbon towards the end of 1487. He did not return to that place until many years afterwards.
“On the other hand, the note is unhesitatingly recognized as in the handwriting of Christopher by such competent authorities as Varnhagen, d’Avezac, H. Harrisse, Asensio, and Cesare de Lollis.
Criticism of the Account by Barros.
“And if Christopher is the author of these notes, they must have been written in 1488, for it was in March, 1488, that King Manuel, in response to an application, cordially invited his ‘especial friend,’ Christopher Columbus, to come to Lisbon, promising him protection against all criminal and civil proceedings that might be taken against him. Columbus, when he received this royal invitation, was at Seville, where his son Ferdinand was born unto him on September 28, 1488. If he left Seville soon afterwards, he may certainly have been present on the memorable occasion, in December, 1488, when Bartholomeu Dias rendered an account to the king of the results of his hope-inspiring voyage.
“If then, Bartholomeu Dias returned in December, 1488, after an absence (according to De Barros) of sixteen months and seventeen days, he must have started towards the end of July or in the beginning of August, 1487; and if the Bartholomeu Dias referred to in the royal rescript of October 10, 1486, is the discoverer of the Cape, which hardly admits of a doubt, he cannot have started in July, 1486, as usually assumed. He cannot have been in Lisbon in December, 1487.
“This date (namely 1488) is further confirmed by Duarte Pacheco Pereira, the ‘Achilles Lusitano’ of Camoens, for in his Esmeraldo de Situ Orbis, written soon after 1505, but only published in 1892, we are told that the Cape was discovered in 1488. And Pacheco is a very competent witness, for Dias, on his homeward voyage, met him at the Ilha do Principe.