I would submit that the Chinese actually learned from the Romans. Roman soldiers who disappeared after a famous defeat founded a city in eastern China, archaeologists say .
The phantom legion was part of the defeated forces of Marcus Licinius Crassus, according to the current edition of the Italian magazine Archeologia Viva .
The famously wealthy Crassus needed glory to rival the exploits of the two men with whom he ruled Rome as the First Triumvirate, Pompey the Great and Julius Caesar .
Crassus decided to bring down the Parthian Empire - a fatal choice .
His forces were routed in 53 BC outside the Mesopotamian city of Carre - today's Harran - and he was beheaded .
According to the Roman historian Pliny, the Romans who survived were taken to a prison camp in what is now northern Afghanistan .
When Rome and Parthia sued for peace in 20 BC - 33 years after Crassus's last battle - all trace of the prisoners had disappeared .
The survivors of Crassus's legion became a mystery, walking ghosts in Roman legends. A Chinese historian in the Han Empire, China's second dynasty, provided an answer to the riddle in the early 3rd century AD .
The historian, Bau Gau, wrote that a Chinese war leader defeated a group of soldiers drawn up in typical Roman formation .
Crassus's old troops must now have been in their fifties and sixties .
Bau Gau said the foreigners were moved to China to defend the strategically important eastern region of Gansu, near today's city of Yongchang .
This is where the survivors founded the city of Liquian, the only site in China where the mark of Ancient Rome can be seen. 'Liquian' is said to mean 'Roman' .
The city has been virtually unknown outside China although hundreds of people visit it each year, admiring traces of defensive wallworks and pieces of broken pottery .
The Caucasians have always been in China and predate the Han themselves in the Gansu region.
From the excellent book The Tarim Mummies, page #281:
"...Narin Infers that they (Caucasians) had been there at least since the Qijia Culture of c. 2,000BC and probably even earlier in the Yangshao Culture of the Neolithic. This would render the Tocharians as virtually native to Gansu (and earlier than the putative spread of the Neolithic to Xinjaing) and Narin goes so far as to argue that the Indo-Europeans themselves originally dispensed from this area westwards."
While I love a good yarn as much as the next man, the fate of prisoners in ancient times never resulted in a 'prison camp' where all the defeated army was kept together. Too much trouble to maintain them, feed them, etc., not to mention the possibility of an armed uprising.
However, there was a great market for slaves to fill the coffers of the winner (with a little booty for the common soldiers)
On the other hand, some victorius generals simply liked to slaughter the defeated army.