This should not surprise anyone. The "XiongNu" as the Chinese call it during the Han Dynasty had blonde hair (at least some do). After Han Wudi defeated the Xiongnu, it broke up into 3 tribes, one went east and became the latter Mongolians.
I know there are many Chinese poems about the green eyes of the Han Emperors. BTW, the Xiongnu were the fiercest fighters of their period.