Heliodorus or Garuda stone pillar, 2nd BCE, Besnagar, M.P - earliest pillar in India

The discovery of a pretty old stone pillar - over 2,000-year-old  (locally known known as Khamba Baba), was one of the most exciting archaeological discoverers made during the colonial period. It throws light on  the Indo-Greek relations in those days. It  also not only suggests  the popularity of the cult of Vasudeva but also marks the growth of  pillar  architecture in India.  From the  Besnagar we understand  the history of the Bhāgavata Sect in India  that had become well established  by  the 2nd century BCE, and the primary Hindu deity being Vāsudeva.  Besnagar, it seems, became functional center of the Bhāgavata or the Pāñcarātra Sect. 

Often referred to as the Heliodorus pillar, it is presumably the oldest  stone column dated back to around 113 BCE in central India. it is named after  Heliodorus, who was an ambassador of the Indo-Greek king Antialcidas from Taxila.  He was sent to the kingdom of Indian ruler Bhagabhadra.  

The pillar that is located in  Besnagar (near Vidisha, Madhya Pradesh) was known as   the Garuda-standard by Heliodorus, as there was  deity of Garuda (the vahana of Vishnu) atop the pillar.  The image of Garuda is missing and  on display in the  Gujari Mahal  museum in Gwalior.  What is surprising is the  Heliodorus pillar site is  near the confluence of two rivers, close to  Bhopal and  the Buddhist stupa of Sanchi, and 4 km  from the Hindu Udayagiri site 

Why was the pillar built? The pillar was erected to glorify the Indian ruler and  the Brahmi inscription on the pillar  suggest the pillar was part of dedication to a supreme deity Vasudeva (Vishnu) the Deva deva (the ''God of Gods).  The pillar or stambha is symbolic of the totality of the deity and the  confluence of  earth, space and heaven on an axis.

.Garuda pillar,dreamstime.com

 Heliodorus pillar cropped upload.wikimedia.org

Above image:  Heliodorus pillar, Vidisha, Madhya Pradesh; late  2nd CE. First brought to light by the famous archaeologist and colonial officer Alexander Cunningham,  during  Archaeological excavations between 1874-1875. He noted  the pillar was encrusted with ritually applied red paste (vermillion).  Apparently, it  was  an  object of worship and ritual animal sacrifice. During the  second survey in 1909-1910 after a big hiatus,  the workers, for the first time,  cleared  red crust and after cleaning found Brahmi script inscriptions about Heliodorus, etc. The Brahmi inscriptions were found on the octagonal surface just below the lower ornamental band of half-rosettes.  Third survey in 1913-1915 confirmed that  it was a major site of worship. The pillar about 17.7 feet extends below the platform and sits on the ancient pillar that was damaged during flooding. The platform itself was 3 feet above the ground and 12 feet wide. The pillar shaft is supported by two placement stones held together with a layer of stone-metal.  After the fourth survey in 1963- 1964, the archaeologists concluded that the Heliodorus pillar itself was one of eight pillars, all aligned along the north-south axis and they were of the opinion that the Besnagar Heliodorus pillar was a part of a more extensive ancient temple site as confirmed by various artifacts discovered here.. ....... 

one of the oldest images of Garuda. upload.wikimedia.org

Above image: Relief depicting a portable Garuda pillar, one of the oldest images of Garuda, Bharhut, 100 BCE. This may have been similar to the Garuda capital of the Heliodorus pillar.....

Heliodorus pillar upload.wikimedia.org

The ancient stone pillar was  discovered during two major archaeological excavations in the 20th-century.  The pillar was  part of an ancient Vāsudeva temple site, a place of worship and veneration. 

Apart from the epic scriptures of the Bhagavad Gita, the epigraphical inscriptions on the Heliodorus pillar and the Hathibada Ghosundi Inscriptions bear testimony to the earliest references to the concept of  Vāsudeva-Krishna devotion and early Vaishnavism. It is the very first archaeological finding of the worship of  Sri Krishna and Vasudeva and   the Heliodorus pillar is associated with  Vasudeva temple.

The Heliodorus pillar lacks tapering and polishing unlike the ancient Ashokan pillars found in India. Further, it is also about half the diameter of Ashoka pillars  .

https://thewire.in/history/how-the-historic-pillar-of-heliodorus-became-khamba-baba

https://en.wikipedia.org/wiki/Heliodorus_pillar.