The word ‘circumnavigation’ nowadays belongs to the same category as marathon-running and Everest-climbing: feats of sometimes egomaniacal endurance with no practical purpose, save sometimes to raise money for charity. However, charity was very far from the minds of the first men to circumnavigate the globe. When Ferdinand Magellan, a Portuguese captain in the service of the king of Spain, set out from Seville in 1519 in search of a westward passage to the Indies, he had a single motivation: profit. It was more than a quarter of a century since Columbus had reached the Americas. But with Mexico still uncolonised and the silver mines of Peru yet to be discovered, Spanish sights remained fixed on the marts of Asia and a share in the lucrative trade in spices, on which their Portuguese neighbours had established a stranglehold.