This monument was built as a kushak (hunting lodge) and observatory by Feroz Shah Tuglak. Later legend turned it into Pir Ghaib. This is also a place that was the centre of action during the siege of Delhi in 1857. From the 11th of May to early June the Ridge was under the control of the citizens of Delhi and the sepoys. However, following the Badli ka Serai battle, the ridge was abandoned and later occupied as a strategic position by the British, who then lay siege to the walled city of Delhi. The Pir Ghaib was one of the places occupied by them and used as an outpost. The heavy battery used by the British, during the siege was stationed very near the Observatory. The lane behind the observatory was within easy access of firing from the walled city, and was termed the Valley of Death by the British soldiers (H.C. Fanshawe (1902), Delhi- Past and Present).
The British clearly identified the Pir Ghaib monument as an observatory, although there are also many disparaging British references to the monument as a “so called observatory”. The book Delhi: Past and Present, by H.C. Fanshawe mentions a report by an earlier British traveler Finch, who talks of a cylindrical structure in the Observatory and the presence of a globe and a half Moon on its top. There are two water colour drawings in the British Library, India Office at London, of the Observatory, made in 1857, by Francis Latter Tandy. There is also a sketch by J.R. Turnbull, of a view from the Flagstaff Tower, of the Observatory, the nearby Chauburji Mosque and Bara Hindu Rao’s house. (Copies of these sketches, if obtained from the India Office of the British Library and preserved in the archives of the Archeological Survey of India, would be useful for further historical researches in this connection).
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