In 1421, a massive Chinese armada set out on an epic voyage of discovery. Huge nine-masted teak junks with red silk sails, accompanied by smaller craft carrying horses or food, rounded the Cape 66 years before Bartolomeu Dias made landfall in the Americas, 70 years before Christopher Columbus, and circumnavigated the globe nearly a century before Ferdinand Magellan set out to find a route to the Spice Islands.

The fleets were commanded by five eunuch admirals who had been ordered by emperor Zhu Di to find new worlds and collect tribute from „the barbarians beyond the seas“. Each admiral taking on a different mission, they sailed down to Australia and to Antarctica. They sailed round the Cape, westward to South America, the Caribbean, both coasts of North America, and up to the Arctic.

Wherever they went, these explorers left evidence - often shipwrecks, for many of the junks foundered - but also carved pillars, seeds, skills, even settlers. When the remnants of the fleet limped back to China two years later, the admirals found a changed world. The emperor was dead. The mandarins who advised the new emperor had no interest in the outside world and destroyed nearly all records of these voyages. China turned in on itself, and knowledge of the voyages was forgotten.

This is the theory of Gavin Menzies, a British Royal Navy submarine commander with an interest in ancient maps, and it is now turning received historical wisdom on its head. It was a Portuguese chart dated 1424 showing islands the Portuguese only „discovered“ decades later that set Menzies on a search for an explanation.

It is Menzies‘s contention that Dias, Columbus, Vasco de Gama and the rest of the pantheon of 15th and 16th century European explorers were not sailing into the unknown; they were following Chinese maps.

Mapmakers copied one another‘s work. If a trader, encountering a Chinese treasure fleet in an Indian port, returned to Venice with a Chinese chart showing a couple of large islands north of a land mass in the Southern hemisphere far west of Europe; and if he sold the chart to a mapmaker; the mapmaker would, in the normal course of affairs, duly include the islands in his own chart, while a colleague in Lisbon would pick them up for his version. By Roman Liptak, Pretoria