The reshaping of the Mediterranean in the wake of the Black Death was a slow process. In addition to political changes within the Mediterranean, notably the expansion of Ottoman power, events taking place beyond the Straits of Gibraltar would, in the long term, greatly transform the life of those who lived on its shores and in its islands. The opening of the Atlantic had already begun in the decade before plague arrived, with voyages down the coast of Africa to the Canary Islands, and it continued with the discovery and settlement of Madeira and the Azores by the Portuguese in the early fifteenth century. As sugar plantations developed on Madeira, it became possible to supply Flanders and other parts of northern Europe directly from the Atlantic with one of the costly products that had previously been obtained within the Mediterranean. By 1482, with the establishment of a Portuguese fortress at São Jorge da Mina (‘the Mine’) in West Africa, not far north of the Equator, gold was beginning to reach Europe without being channelled across the Sahara and through the Muslim ports of the Maghrib; the opening of this Guinea trade compensated for disappointment at the failure of Ceuta to pay for its upkeep. The Atlantic also became a source of slaves for Mediterranean masters: Canary Islanders, Berbers from the opposite shores of Africa and, increasingly, black slaves carried north from the Mine. Many of these eventually reached Valencia, Majorca and other Mediterranean ports, after passing through Lisbon. Then, with Columbus’s entry into the Caribbean islands in October 1492, Castile also acquired a source of precious metal that was ruthlessly exploited by imposing heavy taxes in gold on the Indians, even though they were supposedly free subjects of the Crown. The Genoese, despite their unpopularity in Spain, installed themselves in Seville and, with royal approval, ran the trans-Atlantic trading operations. At the same time, they turned their hands to finance. Turkish pressure on the Genoese possessions in the eastern Mediterranean increased, and so the Genoese allied themselves more insistently with Spain, the power that seemed best able to stand up to the Turks.