Heliodorus was the Greek ambassador of Indo-Greek king Antialcidas Nikephoros of Taxila in the court of Sunga King Bhagbhadra. He erected famous votive Heliodorus pillar around 110 BC near Vidisha, Madhya Pradesh.
The Puranas is important as they were the main influence in the development from early Vedic religion to Hinduism
The Shastras contained works of science and philosophy
The Bhagvad Gita a later addition to the Mahabharata enshrines a philosophical doctrine and in it are described the three paths to salvation: karma, gyan and bhakti