Tim Luard uncovers the forgotten story of China's age of exploration.
Friday 3 June, 11am - 11.30am
In 1405 a 300-strong fleet of giant treasure ships set out from the Chinese port of Nanjing on the first of seven epic voyages to western Asia, Africa and Arabia. China had embarked on a golden period of exploration and trade and became the most advanced sea-faring nation in the world.
The commander of this fleet was a scholar, a diplomat, a warrior - and a eunuch. His name was Admiral Zheng He. Six hundred years later, as the country finally opens its doors again to the world, Tim Luard visits China to tell the extraordinary story of its greatest explorer.
Tim Luard on Swimming Dragons
China is celebrating the 600th anniversary of its greatest adventurer, the "Three-Jewel Eunuch Admiral", and hailing him as the inspiration for its current success.
Almost a century before Columbus and the great Western age of exploration - at a time when China was the richest and most advanced country in the world - Zheng He sailed further than anyone before him, at the head of an armada bigger than the combined fleets of all Europe.
His giant "treasure ships" - packed with the finest goods and most sophisticated weaponry of the time - went to 37 countries over 28 years, exacting tribute for the Dragon Throne and extending China's influence across much of the globe.
But around the time of his death a new Chinese ruler, suspicious of the outside world, banned all further expeditions, ushering in five hundred years of isolation and leaving the way open for countries such as Spain and Portugal - and later Britain and America - to rule the waves instead.
While he remains little-known to most people even in his own country, Zheng He is now being turned into a communist hero and held up as the pioneer of the open-door policies that have brought China once again to the brink of being a world power.
The remarkable story of his life - now the subject of a BBC Radio 4 documentary - may indeed contain clues as to what sort of modern superpower the land that still calls itself the Middle Kingdom will become.
Zheng He was born in the poor, mountainous Chinese province of Yunnan in 1372, just as Genghis Khan's Mongols were being overthrown by a new, home-grown dynasty, the Ming.
His family were muslims from Central Asia who had fought for the Mongols. When Ming armies came looking for rebels they captured the ten-year-old boy and, as was the custom with young male prisoners, castrated him.
"He was ashamed of being a eunuch", according to Professor Liu Ying Sheng of Nanjing University, who says there is little information about this aspect of Zheng He's life.
"All we know is that he was sent to serve the emperor's son at his military base in Beijing... And when this prince later attacked the capital, Nanjing, and took over power as the Yungle Emperor, Zheng He so distinguished himself in battle that he ended up as one of his closest aides".
The new emperor was keen to prove his legitimacy and show off his empire's wealth and power. He also wanted to develop trade - something previously despised.
The chief court eunuch was promoted to admiral and told to produce a fleet to sail to the Western Seas.
I went to visit the dry docks where Zheng He built his ships, alongside the Yangtze River just outside Nanjing. Two 30-foot (11 metre) rudders, still intact after 600 years, were recently found there beneath a thin layer of muddy, frog-filled water.
Ming dynasty records show that each treasure ship was 400 feet (122 metres) long and 160 feet (50 metres) wide. Bigger, in other words, than a football pitch.
Some say no ship that size could be seaworthy. But we do know that they were larger than any ships before them and many times the size of those sailed later by Columbus.
They were better equipped too, with magnetised compasses and watertight bulkhead compartments of a kind the West would have to wait hundreds of years for. They even had their own on-board vegetable patches.
In 1405 Zheng He set out with a fleet containing more warships than the Spanish Armada on the first of seven epic voyages.
From the top of a seven-story pagoda, I looked down at the broad brown Yangtze and imagined the spectacle as the Treasure Fleet of the Dragon Throne made its way towards the blue-green of the ocean.
On board the 317 ships, with red sails and silk pennants at every mast, were 28,000 men with orders to proceed to the ends of the earth to collect tribute from the barbarians beyond the seas.
In his bestselling book '1421' former British naval officer Gavin Menzies claims Zheng He's ships ended up by reaching America and circumnavigating the world.
While some specialists agree that the Chinese got to Australia 300 years before Captain Cook, most believe many of Mr Menzies' claims remain unproven.
But Zheng He did sail throughout Southeast Asia and the Indian Ocean, and on to the Persian gulf and Africa, creating new navigational maps, spreading Chinese culture and bringing home discoveries, treasures and tribute ranging from eye-glasses to giraffes.
He opened up trade routes that are still flourishing today and gained strategic control over countries that are now once again looking to China as undisputed regional leader.
In the sleepy Malaysian port of Malacca - once known as the Babylon of the East - Dr Tan Ta Sen is building a museum on the site where the treasure fleet unloaded its cargoes of Chinese teas, silks and jades... and on its return voyage, Arabian gems, Indian textiles and Indonesian spices.
The Chinese also brought a plaque proclaiming Malacca to be a vassal state of the Ming Emperor.
"Malacca was threatened at the time by Siam. The Chinese promised protection as well as prosperity, so our leaders didn't mind paying a bit of tribute," said Dr Tan.
While Zheng He's soldiers occasionally stepped in to resolve local power struggles, they were used mainly to intimidate rather than conquer or colonise in the way of later arrivals such as the Portuguese, Dutch and British.
The eunuch admiral became known as "Three Jewels" - in Chinese, San Bao. Some say he is the original Sinbad the Sailor.
Such is his popularity among Southeast Asia's Chinese communities that people still touch his statue for good luck at temples dedicated to his memory.
In Singapore, the Friends of Admiral Zheng He are building a replica of a treasure ship as part of national celebrations of this year's anniversary.
"Asia's role in maritime history has not been recognised", according to the group's leader, Chung Chee Kit.
Ever since China decided to call back its fleets it has seen itself as a land rather than sea power and has looked on seafarers and merchants as little more than pirates, he said.
But today things are changing and suddenly Zheng He is a hero in his own country.
China is building its own replica ship and hopes to use it to retrace the original journeys. The man in charge is another Admiral Zheng - a retired naval officer from the People's Liberation Army.
Zheng Ming is working to raise awareness of the Ming Dynasty voyages, now seen as a model for China's "peaceful rise".
"China is calling on its people to blazon forth Zheng He spirit, accelerate the development of the oceanic economy and contribute to the country's reunification, friendly relationships and co-prosperity among good-neighbourly countries", he said.
Zheng He's tomb is a humble affair hidden away in paddyfields outside Nanjing. Almost the only people to visit it till now have been his family - descendants of his adopted nephew.
As we watched a huge new cultural centre being erected next to the tomb, one of them told me how proud he was of his ancestor, who had done so much to "open China to the world".
It had taken a long time, he said, to reassert his rightful place in history.
Swimming Dragons can be heard on BBC Radio 4 on Friday 3rd June at 11.00am