Standing at the center of the Qutub complex in Delhi, the enigmatic rust free Iron Pillar bears many inscriptions, some of which are yet to be studied. According to the oldest inscription in Sanskrit language, written in Brahmi script, the pillar was originally erected as a Vishnudhwaja or the flagstaff of Lord Vishnu in the 3^rd or 4^th century BC, on a hill known as Vishnupadagiri, in memory of a mighty king named Chandra, generally identified as the Gupta emperor Chandragupta II (375-413). A deep socket on the top of the ornate capital indicates that probably an image of Garuda or the ‘Sun Bird’ (the ‘vahana’ or vehicle of Vishnu) was fixed into it.

Basically, for two reasons the pillar is considered by many as an enigma, its high resistance to corrosion and its original location. From the top of its capital to the bottom of its base, the pillar is 23’ 8” (7.21 m), of which 3’ 8” (1.12 m) is below the ground level. Its 2’ 4” high base is fixed on a grid of iron bars soldered with lead to the upper layer of the stone pavement. The diameter of the upper part of the pillar is 12”, the lower diameter is 17” and its estimated weight is more than six tons. In 1997, a defensive fence was erected around the pillar to protect it from the miscreants.

Though the unusual and strange Iron Pillar stands as a precious trophy in the heritage site of the Qutub Complex, its original location is shrouded in mystery and it is also unknown, how it came to its present location. In 1898, J. F. Fleet, an English civil servant with the Indian Civil Services, as well as, a historian and epigraphist, identified Vishnupadagiri with Mathura, for its proximity to Delhi and its reputation as a pilgrimage centre of the Vaishnavites. However, during the Gupta period Mathura was mainly a major centre of Buddhism and the city lies in the plains, there is no hill or giri in Mathura. Due to the paleographic similarity of the inscriptions, it is also theorized that the iron pillar was originally erected in Udayagiri in Orissa. Actually, Udayagiri was closely associated with Chandragupta and the worship of Vishnu was very much common in that area during the Gupta period. In addition to that, there are well-established traditions of mining and working iron in central India. Iltutmish, the successor and son-in-law of Qutubuin Aibak, is known to have attacked and sacked Vidisha in the thirteenth century and probably, he took the opportunity to remove the pillar from Udaygiri, which is less than 10 km from Vidisha town.

However, another theory suggests that the pillar was moved from its original location to the main temple at the fortress city of Lal Kot (Delhi) by the Tomar king, Anangapala II, in 1050 AD. Subsequently, in AD 1191, Anangapala’s grandson, Prithiviraj Chauhan, was defeated by Qutubuin Aibak, the army commander of Muhammad Ghori of Ghazni. Later, when Qutubuin erected Quwwat-ul-Islam Mosque, he moved the pillar from the Tomar temple and placed it in front of the mosque as a victory tower.

The biggest and perhaps the most talked about mystery regarding the Iron Pillar of Delhi is its stunning quality of resistance to corrosion. It is a fact that, one of the most important catalysts for rust is humidity and Delhi is not very humid. Nevertheless, wrought Iron does rust with time, but till today, this pillar seems to be as good as new despite it being 1600 years old. Numbers of Metallurgists, Scientists, Archaeologists and Historians have tried their best to solve this mystery and some of them conclude that it is probably due to the way it was forged by the expert ironsmiths of the ancient India.

It is considered by many that, the complete absence of Sulphur or Magnesium and the high content of Phosphorus prevent the pillar from corroding. Some Metallurgists from Kanpur IIT have observed that, the pillar is actually protected from rust by a thin layer of ‘misawite’, a compound of iron, oxygen and hydrogen. The protective film of misawite formed within three years after the erection of the pillar and has been growing ever since, slowly with time. Presence of high percentage of phosphorous in iron is responsible for the formation of the protective layer. Strangely enough, this film was created by an accident through a complicated combination of the lack of lime in the furnaces used to make the iron pillar, the presence of raw slag and unreduced iron in the pillar, together with the wetting and drying cycles of the weather.

The Iron Pillar in Delhi is probably one of the most amazing structures to have existed through the centuries withstanding the corrosion of time and triggering interest of the curious minds.

Though the unusual and strange Iron Pillar stands as a precious trophy in the heritage site of the Qutub Complex, its original location is shrouded in mystery and it is also unknown, how it came to its present location.