Stambhas (pillars) were set up in the Buddhist sacred places & along the highways. Emperor Ashoka made a major contribution, setting up atleast thirty such pillars.
A stambha consists of a circular column or shaft slightly tapering towards the summit (monolithic). On top of this shaft is the Persepolitan bell or the inverted lotus shaped base. Above this is the abacus on top of which rests the crowning sculpture. These three portions were carved out of a single stone (monolithic).
The stambhas erected during various periods have shown a development in style & structure. Some fine examles are the Basarh Bakhira (with lion capital), Laurya Nandangarh in Champaran district of Nepal (with a seated lion capital on an inverted lotus & carved abacus).
The Saranath stambha with its four lions seated back to back as its crowning sculpture is a fine specimen. Following the Buddhists, the Hindus & the Jains also had columns. (Garuda pillar at Besnagar).
The famous iron pillar from the Gupta period is a fine specimen, withstanding exposure to rain & storm, yet remaining smooth and unrusted bearing testimony to the mastery of Indian metal-casting.