the same Darius, a Greek named Skylax is said to have travelled in India, and to have navigated the Indus in 509 B.C. From his account various Greek writers, among them Herodotus, derived their information about India. In the army which Xerxes led against Greece in 480 B.C. there were divisions of Gandharians and Indians, whose dress and equipment are described by Herodotus. That historian also makes the statement that the satrapy of India furnished the heaviest tribute in the Persian empire, adding that the gold with which it was paid was brought from a desert in the east, where it was dug up by ants larger than foxes.
At the beginning of the fourth century B.C., the Greek physician Ktesias, who resided at the court of Artaxerxes II., learnt much from the Persians about India, and was personally acquainted with wise Indians. Little useful information can, however, be derived from the account of India which he wrote after his return in 398 B.C., as it has been very imperfectly preserved, and his reputation for veracity did not stand high among his countrymen.
The destruction of the Persian empire by Alexander the Great led to a new invasion of India, which fixes the first absolutely certain date in Indian history. In 327 B.C. Alexander passed over the Hindu Kush with an army of 120,000 infantry and 30,000 cavalry. After taking the town of Pushkalavatī (the Greek Peukelaotis) at the confluence of the Kabul and Indus, and subduing the Açvakas (variously called Assakanoi, Aspasioi, Hippasioi, by Greek writers) on the north and the Gandhāras on the south of the Kabul River, he crossed the Indus early in 326. At Takshaçilā (Greek Taxiles), between the Indus and the Jhelum (Hydaspes), the Greeks for the first time saw Brahman Yogīs, or "the wise men of the Indians," as
