Now, in six years, the slow advance of the past sixty was exceeded.[53] Less than four months after his father's death, John, who as heir apparent had drawn part of his income from the African trade and its fisheries, sent out Diego de Azambuga, who in 1482 built under the King's orders the celebrated fort at St. George La Mina. He trafficked with success, but made no great advance along unknown Africa, even if he commenced a new era in the permanent colonisation of the Continent. King John was not disposed to be satisfied with this. In 1484, Diego Cão was ordered to go as far to the South as he could, and not to "wait anywhere for other matters." He penetrated to the mouth of the Zaire or Congo, where he erected (at Cape Padron?) a stone pillar in sign of possession,[54] and brought back four natives to Portugal. These he took out with him in his second voyage (1485); on this expedition Martin Behaim was (wrongly) said to have accompanied him. Cão claimed in this year to have reached 22° S. lat., half way between the Congo and the Cape of Good Hope; but this is probably an exaggeration;--18° S. lat.[55] perhaps marks his furthest point, rather than Walvisch Bay, as in the old tradition. [Footnote 53: It is probably right to ascribe great importance to the work of Fernam Gomez, during his five years' lease. His wealth gave a new character to the equipment of the African Expeditions of Portugal. Formerly there had been too much waste of energy through indefiniteness of object; too much discretion had been left to mariners themselves; now the definite contract for geographical discovery with the Crown caused a more rapid and continuous advance, and long stretches of coast were explored and mapped.] [Footnote 54: According to King John's orders. Wooden crosses (often of Madeira wood?) had hitherto been erected by Portuguese discoverers in new lands. Now stone pillars 6 ft. high were to be used, and on them was to be inscribed, in Portuguese and Latin, the date, with the name of the reigning monarch, and those of the discoverers.] [Footnote 55: Near C. Frio. So it is placed (at _Arenarum Aestuarium_ or _Manga das Arenas_) on Pl. X in Livio Sanuto's _Geographia_ of 1588. We have mentioned that Martin Behaim, of Nüremberg, claimed to have accompanied Cão to West Africa; but his globe, so famous afterwards, executed in 1492 at the order of the Nüremberg Town Council, shows very little evidence of this. Behaim's West Africa is often obstinately Ptolemaic, at the end of the century which had revolutionised the knowledge of this part of the world. He inserts all the legendary Atlantic islands, and puts the Cape Verdes far out of their proper place.]