CE summer temperatures had reached a maximum of . The Landnámabók (Book of Settlement) records disastrous famines during the first century of settlement — "men ate foxes and ravens" and "the old and helpless were killed and thrown over cliffs" — and by the early 1200s hay had to be abandoned for short-season crops such as barley. Atlantic World Christopher Columbus reached the Americas in 1492 under Spanish flag. Six years later Vasco da Gama reached India under the Portuguese flag, by navigating south around the Cape of Good Hope, thus proving that the Atlantic and Indian Oceans are connected. In 1500, in his voyage to India following Vasco da Gama, Pedro Alvares Cabral reached Brazil, taken by the currents of the South Atlantic Gyre. Following these explorations, Spain and Portugal quickly conquered and colonized large territories in the New World and forced the Amerindian population into slavery in order to exploit the vast quantities of silver and gold they found. Spain and Portugal monopolized this trade in order to keep other European nations out, but conflicting interests nevertheless led to a series of Spanish-Portuguese wars. A peace treaty mediated by the Pope divided the conquered territories into Spanish and Portuguese sectors while keeping other colonial powers away. England, France, and the Dutch Republic enviously watched the Spanish and Portuguese wealth grow and allied themselves with pirates such as Henry Mainwaring and Alexandre Exquemelin. They could explore the convoys leaving the Americas because prevailing winds and currents made the transport of heavy metals slow and predictable. In the colonies of the Americas, depredation, smallpox and others diseases, and slavery quickly reduced the indigenous population of the Americas to the extent that the Atlantic slave trade had to be introduced to replace them — a trade that became the norm and an integral part of the colonization. Between the 15th century and 1888, when Brazil became the last part of the Americas to end the slave trade, an estimated ten million Africans were exported as slaves, most of them destined for agricultural labour. The slave trade was officially abolished in the British Empire and the United States in 1808, and slavery itself was abolished in the British Empire in 1838 and in the United States in 1865 after the Civil War. From Columbus to the Industrial Revolution Trans-Atlantic trade, including colonialism and slavery, became crucial for Western Europe. For European countries