If true, his theories would recast the holy trinity of European naval explorers - Captain Cook, Christopher Columbus and Ferdinand Magellan - as followers in the great wake of 15th century China's Admiral Zheng He and his fleet of colossal, nine-masted teak junks. Released earlier this month, Menzies' book, 1421, the Year China Discovered The World, is likely to have a worldwide print run of a million copies. It sits next to Simon Schama's latest on Amazon's best-selling list for history. The TV rights have been sold in Britain. On London's Tube, Menzies' first publishing venture is being promoted as the book that's rewriting history.



In Australia's case, Menzies claims Zheng's vice-admirals, Hong Bao and Zhou Man, beat Cook by almost 350 years. The two men, both eunuchs (as was the custom for captains), arrived in Australia in 1422 - Hong on the west coast, Zhou on the east - and spent several months exploring, landing in several places. Their ships were massive - 122 metres long by 27 metres wide - not that much smaller than a modern aircraft carrier and absolute giants compared with those used by Columbus about 70 years later. The captains navigated by the stars.

Each ship had up to 1000 sailors, who were supplied with fresh vegetables, meat and rice grown on factory ships that accompanied the fleet. Sex was provided by prostitutes who came equipped with sex aids and aphrodisiacs. The Chinese were after treasure, mainly minerals. To assist exploration, Menzies says, they built small villages, complete with observation platforms for surveying, near Gympie in Queensland and Eden in New South Wales. They found lead, silver, semi-precious stones and, in the Northern Territory, uranium. According to Menzies, some of their men formed lasting sexual partnerships with Aborigines, especially in Arnhem Land, where Zhou's ships stayed for several months.

"There's stacks of evidence that they were there," he argues. "Wrecks, plants found in Australia by the first Europeans which had come from China, carved stones, kangaroos in the Chinese emperor's zoo, Chinese jade, figurines and ceramics." Menzies says their visits were recorded by local Aboriginal people in cave drawings found near Sydney and shipwrecks found off Warrnambool, Perth and Byron Bay.

"I think it's absolutely impossible to claim Columbus discovered America, Cook discovered Australia, and Magellan was the first to circumnavigate the world," he says. "You'd have to be a crank nowadays to believe that. They are fairytales. Anyone who objectively looked at the evidence can't say that." But Menzies' evidence is mainly ancient maps, often hotly disputed charts prepared by 15th and 16th century European cartographers. He says they could only have been based on eyewitness reports of Zheng's journeys between 1421 and 1423, which he says predate those of other adventurers. He even identifies the eyewitness, a young and well-connected Venetian called Niccolo da Conti, whose accounts of the Chinese voyages were published on his return to Venice. But Menzies concedes that his research has not uncovered a smoking gun or revealed any single piece of startling new evidence.

The problem is partly of China's own making. Not long after Zheng's fleet set sail, his great supporter, the Emperor Zhu Di, was overthrown by his son Zhu Gaozhi, who reversed his father's expansionist program and, on return of the fleet, ordered that no more voyages be undertaken. All relevant maps were destroyed. What Chinese settlements may have been left in Australia simply died out or were subsumed into Aboriginal society. Faced with the lack of hard evidence from China, Menzies' theory, which has been developing since he saw a mediaeval map of the spheres in Venice 13 years ago, is based on a re-evaluation and reinter-pretation of existing information - a fact that has opened him up to academic criticism.

The head of the map collection in the British Library, Peter Barber, describes Menzies' theories as potentially dangerous, as they seek to rewrite history from outside the bounds of proper scrutiny and academic rigour. He draws a distinction between Menzies and academically trained populist historians, such as Simon Schama and David Starkey. "These theories are not necessarily quite as harmless as people might think," he says. "The consequences can be very grave. You get the big lie. I have met serious scholars who are incredulous of his theories and they can't be bothered to argue, which is a real shame."

Central to Menzies' theories about Australia is a master world map produced in 1542 by Jean Rotz, a French-born cartographer from the Dieppe school, who became map-maker to Henry VIII. The Rotz map, when adjusted for ice and the lack of longitude, accurately shows Australia as Greater Java, Menzies says. But Barber describes the Rotz map as "generally discredited or, at the very least, hotly contested".

"Nowhere does Menzies give any indication that what he says is fact, is in fact controversial. In order to prove something, you need to come forward with the hard evidence." Another map used by Menzies, drawn by Venetian Fra Mauro in 1459, even fails to accurately depict China, a strange occurrence if the Chinese were the source, Barber says. Menzies' views came to light in March this year, when he gave a talk to London's Royal Geographical Society. As luck would have it, the topic sparked interest from Chinese satellite television station Phoenix, which in turn prompted American networks ABC and NBC to report on the theories - and get Chinese feedback. The talks ended up being seen by three million people in China.

"By an incredible bit of luck we got worldwide coverage. That resulted in a flood of information," Menzies says. Soon after that, with the debate raging in Britain and China, his fledgling book on the subject jumped in size from 150 pages to more than 500 pages. He found a publisher and sold the rights for a reported £500,000 ($A1.35 million) to Transworld.

But the Royal Geographical Society remains at arm's length from Menzies, despite its obvious opportunity for bragging rights. "The society does not endorse his views," spokesman Elliot Robertson says. "People are saying 'interesting theory, but where is your proof?' We'd like to see further information come forward, not just from him." Establishment indifference to his theories will not stop Menzies - who soon plans to promote his take on Columbus to the Americans - but it nonetheless upsets him.

"It's just balls. It's absolute crap. The establishment has to protect their patch. Nobody who has given us a mauling has read the evidence, read the book." But perhaps the most telling criticisms have come from the Chinese themselves. Admiral Zheng may be virtually unknown in the West, but in China he has been the subject of intense academic scrutiny for centuries.

According to a report in The Times newspaper earlier this month, Menzies' ideas were politely pooh-poohed by many leading researchers during his recent visit to Nanjing. Professor Luo Zongzheng, from the Nanjing Museum, reportedly told Menzies: "So far, there are too many theories about Zheng He, but there are no relics, no boats or anything concrete. So the theories are not convincing." Peter Fray is The Age Europe correspondent.