Retired Submarine Commander and best-selling author Gavin Menzies will be in Shanghai this month to speak at Concordia International School and M on the Bund. TALK interviewed the controversial historian about his books 1421: The Year China Discovered the World and 1434: The Year a Magnificent Chinese Fleet Sailed to Italy and Ignited the Renaissance. He also let slip his most audacious theory yet.

University of London history professor Felipe Fernandez-Armesto has described Gavin Menzies’ work as “the historical equivalent of stories about Elvis Presley in Tesco and close encounters with alien hamsters.” On Wikipedia, his books are categorised as 'pseudohistory'. Yet both of Menzies’ works have been phenomenally successful and, he tells us, they’re on sale in 130 countries. “The books sell so well,” Menzies says, “because readers believe them to be true and recommend them.”

The text that both made and tarnished Menzies’ name as a historian was 1421: The Year China Discovered the World. In it, he claims that Emperor Zhu Di sent out his eunuch admirals, led by Zheng He, to chart the world and gather tributes and treasures. These sailors, Menzies says, circled the globe 100 years before Magellan’s expedition, reached America 70 years before Columbus, rounded the Cape of Good Hope, and arrived in Australia and New Zealand 350 years before Cook. He says they also made it to both the Arctic and Antarctica.

Menzies uses a barrage of evidence to support his claims, including unidentified shipwrecks, the spread of species, and ancient artifacts. But his trump card, he tells us, comes from his years in the Royal Navy and his resulting understanding of ocean currents, astral navigation and, especially, cartography.

"Don’t write for your fellow historians. Don’t seek literary recognition.”

It was a map that started Menzies on his revisionist mission. He found a Portuguese map dated 1424 that depicted Antilia, islands situated in the Atlantic. Menzies believes these islands to be Puerto Rico, and that the Chinese were the skilled seafarers that charted them. Yet as John Noble Wilford pointed out in The New York Times, scholars have long known about “the penchant of early mapmakers for sprinkling the Atlantic with islands inspired by legend.”

“Real or mythic,” he writes, “these and other Atlantic islands were believed in before 1421.”

Menzies has found much evidence to fit his thesis, though some is so unconvincing it damages his case. When Jack Hitt, also from The New York Times, visited Menzies at his house, the author showed him a 1507 map by Martin Waldseemüller (pictured above) that depicts parts of Florida and a few Carribean islands, all that Europeans knew of America at the time. The map shows cartoon mountains – “mere place holders, no more literal than the fat-cheeked cherub named Zephir seen puffing along the coast,” according to Hitt – north and west of Florida. “Menzies pointed at these cartoon mountains and said, ‘You can see San Francisco here.'”

Hitt recalls thinking, “it seemed rude to point out that along the length of those supposed mountains near pre-Columbian Frisco, Waldseemüller had written, in bold type, ‘Terra Incognita’.”

Menzies’ approach to history often seems vulnerable to criticisms of what psychologists call a confirmation bias. Once we have a theory, we’re great at recognising evidence that supports it but much worse at seeing evidence against it. Sound research requires weighing up and addressing the evidence against one’s thesis. Yet Menzies says, “I have not made any effort to find arguments against my thesis – there are plenty of ‘historians’ who can do that for me.”

In describing his methodology, Menzies champions independence. “Keep an open mind. Do not seek popularity. Write what you think the evidence shows. Don’t write for your fellow historians. Don’t seek literary recognition. Don’t seek peer review.” It’s a method that helps to mitigate the influence of prevailing, potentially outdated views, but also prevents one from benefiting from the scholarship of others.