The detailed list of peoples included in the satrapies of the Persian Empire, whilst it is more ethnographical than geographical in its character, is sufficient proof in itself of the existence of constant movement between Persia and the borderland of Afghanistan, which assuredly included commercial traffic. This enumeration has been compared with a catalogue of tribal contingents which swelled the great army of Xerxes, an independent statement, and therefore a valuable test to the general accuracy of Herodotus; and it is still further confirmed by the list of nations subject to the Persian king found in the inscriptions of Darius at Behistan and Persepolis. We are not immediately concerned with the satrapies included in Western Asia and Egypt, but when Herodotus makes a sudden departure from his rule of geographical sequence and introduces a satrapy on the remotest east of the Persian Empire, we immediately recognize that he touches the Indian frontier. The second satrapy most probably corresponds with that part of Central Afghanistan south of the Kabul River, which lies west of the Suliman Hills and north of the Kwaja Amran or Khojak. Every name mentioned by Herodotus certainly has its counterpart in one or other of the tribes to be found there to this day, excepting the Lydoi (whose history as Ludi is fairly well known) and the Lasonoi, who have emigrated, the former into India and the latter to Baluchistan. The seventh satrapy, again, comprised the Sattagydai, the Gandarioi, the Dadikai, and the Aparytai ("joined together"), an association of names too remarkable to be mistaken. The Sattag or Khattak, the Gandhari, the Dadi, and the Afridi are all trans-Indus people, and without insisting too strongly on the exact habitat of each, originally there can be little doubt that the seventh satrapy included a great part of the Indus valley. The eleventh satrapy is also probably a district of the Indian trans-frontier, although Bunbury associates the name Kaspioi with the Caspian Sea. It is far more likely that the Kaspioi of Herodotus are to be recognized as the people of the ancient Kaspira or Kasmira, and the Daritæ as the Daraddesa (Dards) of the contiguous mountains. All Kashmir, even to the borders of Tibet (whence came the story of the gold-digging ants), was well enough known to the Persians and through them to Herodotus.