‘In the year 1497, King Dom Manuel, the first of that name in Portugal, despatched four ships to discover and go in search of spices.’ In such mundane terms did an anonymous mariner record the start of one of the most remarkable voyages ever undertaken, ‘through seas where sail was never spread before’, as the poet Camões put it. Ten months after clearing the bar of the River Tagus, two carracks, a caravel and a supply ship under the command of Vasco da Gama limped into the Indian port of Calicut, twelve thousand miles away. Da Gama and his scurvy-ridden crew had solved the most valuable mystery of European navigation. By rounding the Cape of Good Hope (nicknamed the Stormy Cape by Bartolomeu Dias, who had reached it nine years earlier before pitiless seas drove him back), the Portuguese had straddled the divide between the Atlantic and Indian Oceans and united east and west. The first person the Portuguese encountered on the quayside in Calicut, a Tunisian merchant who had taken the arduous overland route, ejaculated in Castilian, ‘The Devil take you! What brought you here?’

In less than two decades, the Portuguese established themselves as the dominant power in the Indian Ocean, commanding the sea lanes from Ormuz, at the pinch point of the Persian Gulf, and Malindi in east Africa to Malacca, jewel of the Malay Peninsula. In 1510 Afonso de Albuquerque, Portuguese governor of India from 1509 to 1515, captured Goa, the city that would serve as the pivot of the country’s maritime empire for two centuries.

As Roger Crowley’s darting narrative account of this phase of Portuguese expansion makes clear, the country’s pre-eminence derived from little more than seaborne terrorism. Da Gama’s first interview with the samudri of Calicut in