I don't think Chorasmia and Kangju are exactly the same area, as you seem to imply. Chorasmia is centred on the Amu Darya delta south of the Aral Sea; Kangju seems to be north of the Syr Darya: "Tashkent plus the Chu, Talas, and middle Jaxartes basins" according to John Hill at http://depts.washing..._shu.html#sec17 Neighbours, but not the same place. In fact, I have occasionally wondered if Kangju should be identified with the Massagetai.
The interesting thing about this is that Chorasmia was the area that in the Han corresponded to the kingdom of Kangju
They are all part of a broad Iranian-Saka culture. The Chorasmians come into the picture chiefly because of two pieces of art excavated in Chorasmia: a fragment of terracotta relief showing part of an apparently fully-armoured cataphract cavalryman, dated (I believe by the excavator) to the 4th-3rd century BC, and so (if the dating is correct) the earliest example of the full cataphract panoply; and another fragment given the same date, showing an unarmoured cavalryman wielding his lance in both hands - if dated correctly, perhaps the earliest representation of the cataphract's two-handed kontos. I have no idea what criteria were used for the dating, nor whether dates assigned in the 1970s still hold up.
The Chorasmians were not nomads but rather agriculturalists - it has been suggested that the cataphract was developed by them to counter steppe light cavalry (e.g. the Xiongnu?).
Is there then a link between the Chorasmians and Kangju?
Whether or not the Kangju were cataphracts, the Han would have come into contact with Kushan cataphracts, surely. The Yuezhi had probably not adopted cataphract equipment when they migrated west, but the figure on the Khalchayan relief (probably 1st century AD) and other evidence suggests they would have had it by the time Ban Chao encountered a Kushan army.
If so, then this would add a new dimension to the participation of Kangju cavalry reinforcements on the Xiongnu side during Chen Tang and Gan Yanshou's siege of Zhizhu Chanyu's fort. It would suggest that the Han armies had come into contact with cataphract cavalry in the form of Kangju armies.
The surprising thing, to me, has always been why China and the eastern nomads seeemed to adopt the cataphract panoply so much later than everyone else.
The normal theory is, rather, that the Seleucids got the cataphract from the Parthians: the first time that kataphraktoi hippeis are mentioned in any Greek source is in Polybios' account of the battle of Panion in 200 BC, a few years after Antiochos III's eastern campaign which temporarily subdued the Parthians - hence the implication that he got the new style from them (or from the Graeco-Bactrians, whom he also fought against). Although there are descriptions of Achaemenid cavalry with partial horse-armour for the head and chest only - see Xenophon's description of Cyrus the Younger's guard in the Anabasis - the case for the Achaemenids having the complete cataphract panoply is not very strong at all.
The Seleucids would have gotten the cataphract from the Achaemenid Persians conquered by Alexander.
Edited by DuncanHead, 05 October 2005 - 10:32 AM.