Gavin Menzies: mad as a snake - or a visionary?

His first book claimed that the Chinese discovered America. Now, in a controversial sequel, Gavin Menzies says they also sparked the Renaissance

Gavin Menzies does not look robust enough to take the brickbats that are surely coming his way.

Six years ago, the retired submarine commander caused apoplexy among historians with his controversial theory that vast fleets of Chinese adventurers in multi-masted junks beat Christopher Columbus to the Americas and mapped the entire world centuries before the European explorers. It made him rich and infamous.

Whole websites sprang up devoted to debunking his claims. Scholars called him a fantasist.

Felipe Fernandez-Armesto, professor of history at the University of London, dismissed his book, 1421: The Year China Discovered the World, as "the historical equivalent of stories about Elvis Presley in Tesco and close encounters with alien hamsters".

But while boiling oil was being poured on him from the ramparts of academe, Menzies's book was surging up the bestseller list. It has sold a million copies worldwide, and run to 24 editions in 135 countries.

"I get criticised for being a charlatan and making millions," he says wearily. "But people are astute and if my theories were false and didn't stack up, I would soon know about it from the public."

Every day, 2,000 people go to his website, www.1421.tv - which was set up to deal with the response to the book - pouring in new evidence and ideas. "It is staggering," he says. "Conceited as it may sound, people now think of us as a centre for collating evidence on this period of European and Chinese history."

Menzies, 71, could have anointed his bruises, pulled up his stumps and gone to live in Venice on the proceeds of 1421, satisfied that his revisionist view of history had at least got a good airing.

Instead, he has ploughed his profits into more research and produced an equally contentious sequel, 1434, claiming that the Chinese, once again sailing under the eunuch Admiral Zheng He, sparked the Italian Renaissance and that Leonardo da Vinci's inventions were directly influenced by Chinese technical drawings.

While the eyes of the world are on the exploits of modern China as host of the Beijing Olympics, Menzies is providing the historical counterpoint. What drives him? Is he, as some critics have suggested, "mad as a snake" or a sincere visionary?

"I think one's got to hold on to one's nerve and keep going," he says. "Some of the attacks were vitriolic. I was accused of manufacturing the evidence. I got so ferociously attacked that I decided to defend myself by putting the new evidence on the website as it piles in.

" Much of the critical flak has come from the National University of Singapore and from academics in New Zealand. But Menzies has academic supporters, too, especially in China and America.

The worse the battering he gets from historians, the more people want to know what the fuss is all about. Advance warning of a television documentary called Junk History, shown by the Australian Broadcasting Corporation in 2006, prompted Menzies to alert the website's 13,000 subscribers.

"It was a carve-up," he says. "They completely tore me and my then publishers, Transworld, to shreds. We apologised to our website friends and said if you want to cancel your subscription, we will understand. Only one person cancelled.

That night, we had a huge number of new subscribers and sales of the book in Australia trebled, making it the biggest-selling history book in that country. People want to make up their own minds."

In 1421, Menzies argues that the 107-strong armada of Zheng He's sixth voyage of exploration reached Latin America, the Caribbean and Australia, circumnavigating the globe a century before Ferdinand Magellan, leaving wrecks and artefacts and establishing colonies.

He believes Columbus, Magellan and James Cook all had maps before they set sail - based on a Chinese original. The new book, 1434, is not so sensational but more far-reaching. In it, he contends that Chinese advances in science, art and technology - brought by a cultural delegation that sailed first to Cairo and arrived in Tuscany in 1434 - shaped the Renaissance.

"The idea that Europeans dreamed up everything in the Renaissance is just to make history more romantic," says Menzies. "There's going to have to be an agonising reappraisal of the Eurocentric view of history."

Under his urbanity there is a thin skin. "I got terribly upset when people called me a crank in the early days. It is just amazing how splenetic academics can be. Such a different world from the Navy. If I had been in charge of destroying 1421, I would have said: 'Well, it's a very interesting book and it's a good read.

But the Chinese went home, they didn't colonise the world. History wasn't affected. That was the end of it. So what?' But they handled it badly by trying to undermine me. The man in the street thought he'd better find out about this unknown writer."

It is easy to see why Menzies could be the victim of academic snobbery. He left school at 15, with no qualifications, to follow his father into the Navy, becoming a commander of submarines.

He became fascinated by Chinese navigation on a silver wedding trip to Beijing, where he first heard about Zheng He. His sprawling book on the subject took 11 years to write and was unpublishable.

But his agent refined it to the year 1421 and secured a £500,000 advance from Transworld, a colossal sum for the first-time author of a work of non-fiction. The usual advance for a history book is between £20,000 and £30,000.

"The response is fairly natural," he says. "If some university don had tried to lecture me on submarines, I would have said: Who is this screwball? I can understand their lack of enthusiasm. Also, if you have written about Columbus's discoveries and you are told he had a map, you would think: this is grotesque."

A further annoyance is that Menzies produces riveting reads with copious reference sources and appendices. "This kind of revisionist view of history is very popular and makes people think," says his literary agent, Luigi Bonomi.

"It probably does a lot more to inspire people to approach history than any dry academic tome, even if they disagree with his theory. Gavin is a phenomenon. He genuinely believes he is right and offers some very fascinating insights. People think he must be in the pay of the Chinese government but he pays for all his own flights. He is out there on a mission statement."

Menzies has been made an honorary professor of Yunnan University, in south-west China, and been given the freedom of the city of Kunming. He has carried out 62 major foreign tours - mostly to China, America and the Far East - since 1421 came out in 2002, and is in demand for speaking engagements.

Critics tried to stop his presentation to the Library of Congress in Washington in 2005 from going ahead, and security guards were doubled to prevent his talk being disrupted.

To date, 1421 has been the subject of eight television documentaries. The film rights have been bought by Warner Bros.

Menzies's ordered life as a retired seaman has been turned upside down. He works harder, lives more healthily and spends alarmingly. "Before this book came along, I used to drink far too much, two bottles of vino a day. For the past six years, I have started work at 6am and gone through to 7pm. Boozing time is dramatically curtailed."

He has sunk almost £2 million into research. Recently, he commissioned radar studies off the coast of Oregon to establish whether a shipwreck identified by an American, Dave Cotner, is a Chinese junk.

The wood samples were in such poor condition it was impossible to tell, so Menzies is now faced with raising money for a complete excavation. "There's no end to it," he says.

Menzies and his Italian wife, Marcella, have been round the world six times in pursuit of his Chinese adventure. Their five-storey north London home has become the hub of the history machine, with an entire room given over to files of evidence on the top floor and a team of four graduates working full-time in the basement.

"They have assembled into a coherent whole the avalanche of assorted evidence that pours in," he says. "They are head and shoulders better than I and my friends were at a similar age - we were mostly irresponsible drunken ruffians."

Some reviewers suggest that Menzies's strength is that he links known facts that no one has had the wit to put together before and comes up with something worth debating. Others have called his books a tower of hypotheses. But his brand of history as detective thriller, with clues being provided by a fascinated public, has its own peculiar momentum.

It was Henry Adams, the novelist and historian, who said that history will die if not irritated. "The only service I can do to my profession," he said, "is to act as a flea." Menzies is a very troublesome flea indeed, and possibly an important one.

• '1434: The Year a Magnificent Chinese Fleet Sailed to Italy and Ignited the Renaissance' by Gavin Menzies (HarperCollins) is available from Telegraph Books for £18 + £1.25 p & p. To order, call 0870 428 4112 or go to www.books.telegraph.co.uk