Seven major pillar edicts have been found at Lauriya-Araraj, Lauriya Nandangarh, Rampurva, Nigali Sagar, Sarnath, Topra, and Meerut. Ashokan pillars probably signify the axis of the world (axis mundi) that separated heaven and earth.
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 Mauryan art is believed to be inspired from Achaemenid or Persian influence. We can find a lot of similarities in terms of form and style in the inscriptions of Ashoka and the Persian king Darius.