In ancient Greek geography, the basin of the Indus River (essentially corresponding to the territory of modern Pakistan) was on the extreme eastern fringe of the known world. The first Greek geographer to describe India was Herodotus (5th century BC), who calls it ἡ Ἰνδική χώρη hē Indikē chōrē, after Hinduš, the Old Persian name of the river and the associated satrapy of the Achaemenid Empire. Darius the Great had conquered this territory in 516 BC, and during the 5th century BC, Greek knowledge of India was entirely received by contact with the Persian empire (according to Herodotus 4.44, via Scylax of Caryanda, a Greek explorer who sailed down the length of the Indus in the service of Darius). The Greeks (or Persians) were not aware of the geography of India (or Asia in general) east of the Indus basin. Herodotus in 4.40 is explicit about India being on the eastern fringe of the inhabitable world,
In book 3 (3.89-97), Herodotus gives some account of the peoples of India; he describes them as being very diverse, and makes reference to their dietary habits, some eating raw fish, others eating raw meat, and yet others practicing vegetarianism. He also mentions their dark skin colour.
In 3.38, Herodotus mentions the Indian tribe of the Callatiae for their practice of funerary cannibalism; in a striking illustration of cultural relativism, he points out that this people is just as dismayed at the notion of the Greeks practicing cremation as the Greeks are at that of eating their dead parents. In book 7 (7.65,70,86,187) and in 8.113 Herodotus describes the Indian infantry and cavalry employed in Xerxes' army.