Strabo1 says that Roman trade in the Indies was much more consi­de­ra­ble than that of the kings of Egypt, and it is sin­gu­lar that the Romans, who had lit­tle fami­lia­rity with com­merce, were more attu­ned to trade with the Indies than the kings of Egypt had been, who had it, in a man­ner of spea­king, before their eyes. This requi­res an expla­na­tion.

After the death of Alexander, the kings of Egypt esta­bli­shed a mari­time trade in the Indies, and the kings of Syria, who had the eas­tern­most pro­vin­ces of the empire, and conse­quently the Indies, main­tai­ned this trade, of which we have spo­ken in chap­ter vi, which was car­ried on by land and by rivers, and which had been fur­ther faci­li­ta­ted by the esta­blish­ment of the Macedonian colo­nies ; and so it was that Europe com­mu­ni­ca­ted with the Indies both through Egypt and through the king­dom of Syria. The dis­mem­ber­ment which was done of the king­dom of Syria, whence was for­med that of Bactriana, had no harm­ful effect on that com­merce. Marinus the Tyrian, cited by Ptolemy,2 speaks of the dis­co­ve­ries made in the Indies by means of some Macedonian mer­chants. Those which the expe­di­tions of kings had not made, the mer­chants made. We see in Ptolemy3 that they went from the Stone Tower4 to Sera ; and the mer­chants’ dis­co­very of such a remote out­post, situa­ted in the eas­tern and nor­thern part of China, was a sort of mar­vel. Thus, under the kings of Syria and Bactriana, com­mo­di­ties from the south of India pas­sed by the Indus, the Oxus, and the Caspian Sea to the west ; and those of the more eas­terly and nor­therly regions were car­ried from Sera, the Stone Tower, and other inter­me­diate ports to the Euphrates. These mer­chants made their way by hol­ding more or less the for­tieth degree north lati­tude, through coun­tries which are to the west of China, bet­ter cons­ti­tu­ted than they are today, because the Tartars had not yet infes­ted them.

While the Syrian empire was exten­ding its trade so far on land, Egypt was not greatly increa­sing its mari­time trade.

The Parthians appea­red, and foun­ded their empire ; and when Egypt fell under the might of the Romans, that empire was in its prime and had recei­ved its exten­sion.

The Romans and the Parthians were two rival powers which fought not to see which would reign, but which would exist. Between the two empi­res deserts were for­med ; bet­ween the two empi­res, they were always under arms ; far from there being any trade, there was not even any com­mu­ni­ca­tion. Ambition, jea­lousy, reli­gion, enmity, and ethos sepa­ra­ted eve­ry­thing. Thus com­merce bet­ween Occident and Orient, after having seve­ral rou­tes, was left with just one ; and Alexandria having become the only port along the route, that port grew.

He says in book XII that the Romans used one hundred twenty ships for it ; and in book XVII that the Greek kings sent scarcely twenty.

Book I, ch ii.

Book VI, ch. xiii.

Our best maps place the Stone Tower at the hundredth degree longitude and about the fortieth latitude.