Megasthenes was an ancient Greek ambassador and explorer who served at the court of the Mauryan emperor Chandragupta Maurya in the 4th century BCE. He is best known for his work "Indica," which provides a detailed account of Mauryan India, its culture, geography, and social organization. Megasthenes' observations were significant in shaping ancient Greek perceptions of India and contributed to the historical understanding of the region during that time. His writings are among the earliest known Western descriptions of Indian society.