Around 36 BCE, Chinese forces from the Han Dynasty fought a group of rebels called Xiongnu at a fortress in what is now Kazakhstan.
During the battle, the Chinese noticed their enemy employed a strange but distinctive formation. One historian at the battle recalled a unit that formed a unique "fish-scale"-style of protection using their shields.
Some modern historians think that "fish scale" was a Roman phalanx.
The theory does have naysayers. Some believe the DNA could be the result of contact from Silk Road trading between Rome and the Far East. Others say Caucasian Huns and warriors with other racial backgrounds fought through this area of Asia at the time.
At least one expert believes there just isn't enough physical evidence to say these Chinese are descended from Roman legionaries.
"For it to be indisputable, one would need to find items such as Roman money or weapons that were typical of Roman legionaries," Maurizio Bettini, an anthropologist from Siena University, told La Repubblica. "Without proof of this kind, the story of the lost legions is just a legend."