The Seres and their country were named after the central product which sustained their industry, the "Ser" or Silkworm. Some classicists argued that it was extremely improbable that a nation would be named after an insect, and the 19th Century orientalist Christian Lassen identified them in the sacred books of the Hindus as the "Caka, Tukhara, and Kanka".
Mention of the Seres people, as the manufacturers and distributors of silk, is earlier than the country Serica. This made some historians believe that the Greco-Romans named the Chinese Sinae when approached from the Pacific Ocean but Seres when reached from the Asiatic steppes. Others contend that the Seres were a loose confederacy of Tocharian people, who traded with the Indians, the Chinese and, through the Parthians and later the Sassanid Persians, the Romans.
The Seres were universally depicted as prudent, just and compassionate people, whose genteel natures were addicted to comfort (not luxury), peace and harmony. In commerce they were shrewd, yet still more assiduous and diligent. For the Romans, a long and mutually remunerative commerce with the Seres was endangered when the middlemen, the Parthians, were usurped by the Sassanids.
A summary of Classical sources on the Seres (essentially Pliny and Ptolemy) gives the following account:
" The region of the Seres is a vast and populous country, touching on the east the Ocean and the limits of the habitable world, and extending west nearly to Imaus and the confines of Bactria. The people are civilised men, of mild, just, and frugal temper, eschewing collisions with their neighbours, and even shy of close intercourse, but not averse to dispose of their own products, of which raw silk is the staple, but which include also silk stuffs, furs, and iron of remarkable quality." (Henry Yule, "Cathay and the way thither")
Serica was described by Ptolemy as bordering "Scythia beyond the Imaum mountains (Tian Shan)" on the West, "Terra Incognita" to the North-East, the "Sinae" or Chinese to the East and "India" to the South. This would correspond with modern Xinjiang province in North-Western China.
Detail of Asia in the Ptolemy world map. Gulf of the Ganges left, Southeast Asian peninsula in the center, China Sea right, with "Sinae" and "Serica" to the North.
The first accounts of the Seres, of disputed authenticity, seem to be those by the Greek historian Ctesias in the 5th century BC, in which he refers to them as "people of portentous stature and longevity", in his book Indika.
Strabo (circa 20 AD)
The Greek geographer Strabo mentioned the Seres in his "Geographia", written early in the 1st century, in two passages. He also alludes to the longevity of the Seres, said to exceed two hundred years, and quotes from "some writers":
"Onesicritus ... expatiates also in praise of the country of Musicanus, and relates of the inhabitants what is common to other Indian tribes, that they are long-lived, and that life is protracted even to the age of 130 years, (the Seres, however, are said by some writers to be still longer lived), that they are temperate in their habits and healthy; although the country produces everything in abundance." (Strabo, Geographia, Book XV, Chap I).
In one passage on the Greco-Bactrian Kingdom, he mentions that they extended far into eastern Asia, possibly leading to the first known contacts between China and the West around 220 BC:
" In the furthest east of Asia are the Indians, Seres, and Scythians. The Indians and Scythians occupy the two extremities, the Seres are in the middle" (Pomponius Mela, De Situ Orbis, I, 2).
Also, after speaking about the Caspian sea and the Scythian shores:
"From these the course (of the shore) makes a bend and trends to the coast line which faces the east. That part which adjoins the Scythian promontory is first all impassable from snow ; then an uncultivated tract occupied by savages. These tribes are the Cannibal Scythians and the Sakas, severed from one another by a region where none can dwell because of the number of wild animals. Another vast wilderness follows, occupied also by wild beasts, reaching to a mountain called Thabis which overhangs the sea. A long way from that the ridge of Taurus rises. The Seres come between the two; a race eminent for integrity, and well known for the trade which they allow to be transacted behind their backs, leaving their wares in a desert spot" (Pomponius Mela, De Situ Orbis, III, 7).
" Then, we again find tribes of Scythians, and again desert tracts occupied only by wild animals, till we come to that mountain chain overhanging the sea, which is called Tabis. Not till nearly half the length of the coast which looks north-east has been past, do you find inhabited country. The first race then encountered are the Seres, so famous for the fleecy product of their forests." (Pliny the Elder, The Natural History, Chap XX "The Seres").
"The Seres are famous for the woolen substance obtained from their forests; after a soaking in water they comb off the white down of the leaves... So manifold is the labour employed, and so distant is the region of the globe drawn upon, to enable the Roman maiden to flaunt transparent clothing in public" (Pliny the Elder, The Natural History, Chap XX "The Seres").
And he speaks comparatively of what was known in the world at the time about iron and its tempering:
"But of all the different kinds of iron, the palm of excellence is awarded to that which is made by the Seres, who send it to us with their tissues and skins; next to which, in quality, is the Parthian iron."
"They also informed us that the side of their island (Taprobane) which lies opposite to India is ten thousand stadia in length, and runs in a south-easterly direction--that beyond the Emodian Mountains (Himalayas) they look towards the Serve (Seres), whose acquaintance they had also made in the pursuits of commerce; that the father of Rachias (the ambassador) had frequently visited their country, and that the Seræ always came to meet them on their arrival. These people, they said, exceeded the ordinary human height, had flaxen hair, and blue eyes, and made an uncouth sort of noise by way of talking, having no language of their own for the purpose of communicating their thoughts. The rest of their information (on the Serae) was of a similar nature to that communicated by our merchants. It was to the effect that the merchandize on sale was left by them upon the opposite bank of a river on their coast, and it was then removed by the natives, if they thought proper to deal on terms of exchange. On no grounds ought luxury with greater reason to be detested by us, than if we only transport our thoughts to these scenes, and then reflect, what are its demands, to what distant spots it sends in order to satisfy them, and for how mean and how unworthy an end!" (Pliny the Elder, The Natural History, Chap XXIV "Taprobane")
"The inhabited part of our earth is bounded on the east by the Unknown Land which lies along the region occupied by the easternmost nations of Asia Major, the Sinae and the nations of Serice" (Ptolemy Geographia, ca 150 AD).
Ptolemy also positions China (Sinae) quite precisely:
"The eastern extremity of the known earth is limited by the meridian drawn through the metropolis of the Sinae, at a distance from Alexandria of 119.5 degrees, reckoned upon the equator, or about eight equinoctial hours. . . ."(Book vii, ch. 5.)
Ptolemy also speaks of "Sera, the Capital of the Seres".
Geography and economy
As Ptolemy describes it, Serica was bordered in the north by the Annibi and Auxacii Montes, identified as the Altai Mountains. The Montes Asmiraei, a Serican district, are the Da-Uri Chain while the Cassi Montes are believed to be the mountains of the Gobi Desert. Ptolemy names the principal river of the Seres as the Bautisus, identified as the Yellow River.
The Greco-Roman writers name over a dozen tribes and fifteen cities of the Seres. It is evident from their portrayals that they are not all of the same ethnicity but share a common national appellation. Their capital is named as Sera. Possible candidates include Kashgar and Yarkand. Issedon, the capital of the Serican Issedones, is thought to have been situated on the eastern slopes of the Pamirs or even the Altai Mountains, while the third notable city, Aspacara, was described as located near the source of the Yellow River.
The ancient fathers also describe the pleasant climate of Serica and its plenitude in natural resources. Among these are iron, furs and skins, and precious stones.