Megasthenes

Megasthenes (, ca. 350 – 290 BCE) was a Greek ethnographer and explorer in the Hellenistic period. He wrote the work "Indica". He was born in Asia Minor (now Turkey).
Arrian says that Megasthenes lived in Arachosia, with the satrap Sibyrtius. He visited India from there:
"Megasthenes lived with Sibyrtius, satrap of Arachosia, and often speaks of his visiting Sandracottus, the king of the Indians." Arrian, "Anabasis Alexandri" 
At the beginning of his "Indica", he speaks about the older Indians who know about when Dionysus and Hercules arrived in India. This story was very popular during the Alexandrian period. What he says about the religions of the Indians is important. He mentions the devotees of Heracles (Lord Krishna) and Dionysus (Lord Shiva or King Lord Indra). However, he does not mention Buddhists. This could mean that the religion was not well known before Ashoka took power.
Writers like Arrian, Strabo, Diodorus and Pliny refer to "Indica" in their works. Arrian said the best things about Megasthenes, but Strabo and Pliny do not treat him with as much respect. 
Megasthenes' "Indica" is the first well-known description of India by someone from the Western world.