Iron column in Delhi: history, composition of the column, height and amazing resistance to corrosion

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Iron column in Delhi: history, composition of the column, height and amazing resistance to corrosion
Iron column in Delhi: history, composition of the column, height and amazing resistance to corrosion

The Iron Column in Delhi is a historical monument that captivates with the mystery of its creation. It is made of iron that has not rusted since its construction - over 1600 years ago. Despite the fact that the column is in the open air, it still remains strong, which is an excellent confirmation of the scientific and technical knowledge in ancient India. The iron pillar is one of the world's oldest mysteries that archaeologists and material scientists are still trying to solve.

You can see the photo of the iron column in Delhi in our article.

view of the Iron Tower
view of the Iron Tower


The described object is located opposite the Quwwat-ul Islam mosque in the Qutb complex, where the famous Qutb Minar minaret is located, in the Mehrauli archaeological complex in Delhi.

Iron column majesticallyrises to a height of 24 feet (7.2 m). An ancient landmark was made from 6 tons of almost pure wrought iron.

Qutub Minar complex
Qutub Minar complex

Chemical composition

Researchers of this mysterious structure were conducting a chemical analysis of its composition. In 1961, the iron used in the construction of the column was found to be of exceptional purity with a very low carbon content. In addition, scientists have found that the metal from which it was made does not contain sulfur or magnesium, but does include phosphorus. Iron itself accounts for about 99.4%. Among the impurities, phosphorus is the most (0.114%). The proportion of carbon is 0.08%, which makes it possible to classify the material as low-carbon steel. Other impurities are presented in the following quantities:

  • silicon – 0.046%;
  • nitrogen – 0.032%;
  • sulfur – 0.006%.

Scientific theories

Scientists conducting research in an attempt to uncover the secret of the iron pillar in Delhi came to a number of conclusions. All theories put forward to explain the amazing resistance of a structure to corrosion fall into two main categories:

  1. Material factors (these versions are put forward mainly by Indian researchers).
  2. Environmental factors (preferred by foreign scientists).

It is believed that due to the high content of phosphorus, a protective layer is formed on the surface of the column, which, on the one hand, protects it from corrosion, on the other hand, causes metal brittleness (this is clearly seen inthe place where the cannonball hit the column).

According to other scientists, the very weather conditions in Delhi prevent the appearance of rust. According to them, the key catalyst for rust is moisture. Delhi has a dry climate with little moisture. Its content, during most of the year, does not exceed 70%. This may be the reason for the lack of corrosion.

Indian scientists from the Institute of Technology in Kanpur in 2002 conducted a thorough study. They cited a protective layer formed by crystalline phosphate as the reason for the absence of metal corrosion. The process of its formation occurs in the presence of wetting and drying cycles. In fact, the corrosion resistance of this unique structure is due to its chemical composition and weather conditions.

In addition, according to Indian scientists, at that time the blacksmiths did not have any special knowledge about the chemistry of alloys, and the composition of iron was selected empirically.

Thus, this theory suggests that there is a relationship between the processing, structure and properties of the pillar iron. Based on scientific analysis, these three factors have been shown to work together to form a protective passive rust layer on an iron pole in Delhi. As a result, it does not undergo further corrosion. Thanks to this property, the iron column in India can indeed be considered another wonder of the world.

damage on the iron column
damage on the iron column

However, this ability to resist corrosion is not unique to thisstructures. Studies have shown that other large ancient Indian objects have a similar property. These include iron pillars at Dhara, Mandu, Mount Abu, Kodohadri Hill and ancient iron cannons. Therefore, it can be said that the ancient blacksmiths were highly skilled specialists in forging iron products. In a report published in the journal Current Science, R. Balasubramaniam of the Indian Institute of Technology in Kanpur stated that the pillar is “a living testament to the skill of the metallurgists of ancient India.”

Historical Preservation

Earlier, numerous tourists, clinging to the column, tried to hug her, joining their hands. It was believed that if this worked out, it would bring good luck to a person.

However, due to this rather popular custom, the lower part of the column began to change its color from constant friction. According to the researchers, the endless touches and movements of visitors erase the protective layer that protects it from corrosion. In order to avoid further damage to the lower part of the iron pole, a small fence was placed around it in 1997.

Iron column in the 19th century
Iron column in the 19th century


Although several inscriptions have been found on the pillar, the oldest of them is a six-line Sanskrit verse. Since the name Chandra is mentioned in the third verse, scholars have been able to date the column's construction to the reign of Chandragupta II Vikramaditi (375-415 BC), King of the Gupta.

But today she is in Delhi. How did this column get there, and where was itoriginal location - still subject to scholarly debate.

inscriptions on the iron column
inscriptions on the iron column

Riddles of the column

The purpose of the iron pillar is one of the many mysteries of history. Some researchers say that this is a flagpole made for the king mentioned in the inscription. Others claim it was a sundial in its supposed original location in Madhya Pradesh.

Why the column ended up in the capital of India is another mystery of the structure. There is no evidence of who exactly moved it over a thousand years ago, how it was moved, or even why it was moved. All that can be said for sure about this aspect of the pillar's history is that the mysterious iron pillar has been a part of the landscape of the Indian capital for a very long time.

Versions and conjectures

The history of the iron pillar in Delhi is still being researched. There are many versions of its origin. However, despite the presence of various conjectures, scientists already have some information about this structure.

In 1838, an Indian antiquarian deciphered everything written on an iron pillar in Delhi. The inscriptions were then translated into English and published in the Journal of the Asiatic Society of Bengal. Before that, nothing was known about the iron column.

According to scientists, it was created in the early period of the reign of the Gupta (320-495 AD). This conclusion was made based on the style of the inscription on the pillar and the peculiarities of the language. As already mentioned, the third verse of the inscriptionon an iron pillar, scientists found a mention of the name Chandra, which designates the rulers of the Gupta dynasty. However, there are different opinions as to whether the word Chandra refers to King Samudragupta (340-375) or Chandragupta II (375-415), who was the son of King Samudragupta. It is also believed that the inscription could refer to the Hindu God Vishnu.

Iron column at sunset
Iron column at sunset

There are also many historians' assumptions about where the pillar was forged. According to one of the main theories, the iron pillar was created on the top of the Udaigiri hill in Madhya Pradesh, from where it was taken to Delhi by King Iltutmish (1210-36) after his victory.

According to other researchers, the iron pillar was moved and installed in the main temple of Lal Kot (the ancient capital of Delhi) by King Anangpal II in 1050 AD. However, in 1191, when King Prithviraj Chauhan, grandson of Anangpal, was defeated by the army of Muhammad Ghori, Qutb-ud-din Aibak built the Kuvwat-ul-Islam mosque in Lal Kot. It was then that the column was moved from its original location to its current location in front of the mosque.

Architecture of iron pillar in India

The structure is placed on a base decorated with artistic carvings. Part of the column, about 1.1 meters, is underground. The base rests on a lattice of iron rods soldered with lead. A layer of paving stone is laid on top of it.

The height of the iron column reaches seven meters. The bottom diameter of the post is 420 mm (17 in) and its top diameter is 306 mm (12 in). The column weighs over 5865 kg. Its top is also decorated with carvings. There are inscriptions carved on the iron stand. Some of them contain vague indications of her origin.

Researchers found that the column was made by molding and forging and welding from pieces of paste-like iron weighing about 20-30 kg. Hammer marks are still visible on the surface of the pillar. It was also revealed that about 120 people worked for several weeks creating this column.

top of the iron column
top of the iron column

Destruction attempt

At a height of about four meters from the ground, there is a noticeable depression on the surface of the column. The damage is said to have been caused by firing a cannonball at close range.

According to historians, Nadir Shah ordered the destruction of the iron column during his invasion in 1739. According to the researchers, he wanted to do this in order to find gold or jewelry. Which the invader thought might be hidden inside the top of the post.

According to another version, they wanted to destroy the column as a Hindu temple pillar, which had no place on the territory of the Muslim complex. However, the iron pillar in Delhi could not be destroyed.