A Roman embassy arrived in Luoyang to emperor Huan (漢桓帝) of the Han dynasty in 166 C.E., that was sent by either Antoninus Pius or his successor Marcus Aurelius (Antoninus Pius died in 161 and the Chinese sources refer to the sender as "Andun", which could also mean Marcus Aurelius, who was also commonly known as Antoninus). This embassy is recorded in Hou Han Shu (後漢書) or the Book of the Later Han.

Later records get a little murky as the Han dynasty collapsed in 220 C.E., but according to the Book of Liang from 635, several merchants who were apparently Romans arrived in the early 3rd century and another embassy also arrived at that time, presumably sent by one of the Severan emperors. Another embassy arrived in 284, presumably sent by emperor Carus.

There were a couple more merchants from the Eastern Roman Empire that arrived in the late 7th and early 8th centuries, dating from the rule of Heraclian dynasty or the period of Byzantine history known as "Twenty Years' Anarchy".

Further reading: Romans and Roman empire in Ancient Chinese sources