RESEARCH ARTICLES CURRENT SCIENCE, VOL. 92, NO. 12, 25 JUNE 2007 1709 *For correspondence. (e-mail: bala@iitk.ac.in) On technical analysis of characters of the oldest Delhi Iron Pillar inscription R. Balasubramaniam 1, * and V. N. Prabhakar 2 1 Department of Materials and Metallurgical Engineering, Indian Institute of Technology, Kanpur 208 016, India 2 Archaeological Survey of India, New Delhi 110 001, India A detailed technical analysis of the characters of the oldest Delhi Iron Pillar inscription has been con- ducted. It reveals that the characters were put on the surface by die-striking operation using dies of different characteristic shapes. The dies were struck more than once to provide each imprint on the surface. Both the die and material surfaces were in cold condition during the operation. Evidences have been provided to con- clude that the inscription was die-struck on the pillar when it was in the vertical erect condition. Keywords: Characters, Delhi Iron Pillar, inscription, technical analysis. THE construction of the Delhi Iron Pillar (Figure 1), now located at the Quwwat-ul-Islam mosque in New Delhi, is a marvellous engineering achievement considering that it was manufactured by forge-welding, 1600 years ago during the Gupta period 1–3 . There are many inscriptions inscribed on the Iron Pillar 2,4,5 . The oldest and largest among these inscriptions is a six-line, three-stanza inscription in Sanskrit (Gupta-Brahmi), which states that the pillar was erected to serve as a standard of Lord Vishnu at a place called Vishnupadagiri. The complete translation of the inscription with critical comments is available elsewhere 1 . The inscri- ption also elaborates the military exploits of a monarch, who is simply referred to as Chandra in the inscription. On palaeographic grounds (i.e. based on the nature of the characters of Gupta-Brahmi), the inscription can be dated to early fifth century AD 6 . Chandra has been identified unam- biguously with Chandragupta II Vikramaditya (AD 375– 414) based on a detailed analysis of the archer-type gold coins of the imperial Guptas (AD 320–600) 1,7 . The original location of the pillar, Vishnupadagiri (meaning ‘Hill with footprint of Vishnu’), has been identified as modern Uday- agiri, in the close vicinity of Besnagar, Vidisha and Sanchi, based on literary, archaeological, numismatic and geo- graphic evidences 7 . Moreover, the Vishnupadagiri (i.e. Udayagiri) site was of astronomical importance as it is located on the Tropic of Cancer 8 . Recent research has shown that the Iron Pillar was located at an astronomi- cally significant position at Vishnupadagiri, such that the early morning shadow of the Iron Pillar fell on the foot of Anantasayana Vishnu in cave 13, only in the time period of the year around summer solstice 9 . Therefore, the Delhi Iron Pillar also highlighted the astronomical knowledge that existed during the Gupta period, apart from providing solid proof of the metallurgical brilliance of this Golden Age of India. In this article, an important problem in Indian history will be revisited using scientific analysis, namely when the inscription was actually imprinted on the pillar. Based on historical and numismatic data, we know that the inscri- ption was not a posthumous one 1 . We will take recourse to technical analysis of the characters of the Iron Pillar inscription to provide additional inputs to understand this issue. The secondary aim of the analysis would be to reveal the method by which the inscription was imprinted on the pillar surface and the engineering design of the charac- ters. Figure 1. The Delhi Iron Pillar located at the Quwwat-ul-Islam mosque in the Qutub Complex at New Delhi. This photograph was taken on a rainy day in August 2006.