@McTag,
Quote:I heard yesterday that one of the gemstones had come from Sri Lanka! That's some trade for the 7th c
That's really not that surprising. India has long been a source of gem stones, and trade between Sri Lanka and the mainland is no stretch, nor is trade along the rather brief and relative tame sea route from the Indus River estuary to the Persian Gulf. Thereafter, overland trade would have accounted for it. The Roman "sub-province" of Iudaea (Judea) was established within the province of Syria, and with a capital at Caesarea Maritima (Jerusalem didn't mean a damned thing to the Romans--except trouble) precisely because of a perceived need to regulate and protect the overland trade from the head of the Persian Gulf (where Basra is today).
Some European paeleontologists believe that "mummified" remains (preserved by the arid climate, and not by intentional embalming) found in the Gansu corridor are those of western European traders from many thousands of years ago. The Chinese will no longer those remains to be examined (it seemed to upset them). Silk was being traded into Siberia in the first millenium BCE.
Ancient traders had exactly the same motivation as modern ones, they just didn't move as quickly.