As a sequence of Alexander's invasions of India a number of Greek travellers visited India. They gave valuable information of India to the outside world. Neachus was deputed by Alexander to explore the coast between the Indus and the Persian Gulf. Onesicritus took part in the voyage with Neachus and afterwards wrote a book about the voyage and India. Megasthanese was sent as an ambassador to the court of Chandragupta Maurya by Seleucus Nikator the Greek ruler of Persia. His account about Mauryan India is compiled in Indika.