Fortifications of Cities in Ancient India
By Udai Narian Roy
Summary
This article surveys defensive architecture in ancient India, dividing fortifications into natural (akr̥tima) and artificial (kr̥tima) types. Natural fortifications exploited geography: water forts near rivers or seas, land forts in deserts, mountain forts protected by hills, rocky prastara forts, cave forts, marsh forts and forest forts. Cities like Ayodhyā, Mathurā, Dvārakā, Pāṭaliputra and Girivraja enjoyed natural defences. Kautilya’s Arthasāstra lists seven categories of natural forts and emphasises that water and forest forts are best for populous centres. Natural defenses, however, were insufficient in the face of frequent wars, so cities added artificial fortifications. These included walls, moats or trenches, and protective forest belts. The Silpaśāstras, Nītisāstras and Purāṇas insist that city walls be built on ramparts formed by digging ditches; Kautilya advises a rampart six dandas high and twice as broad, with parapets spaced 12–24 hastas apart. Walls could be single or multiple; Megasthenes reports that Pāṭaliputra was encircled by three walls. Heights ranged from nine to twenty cubits, with some texts warning against excessive height to avoid darkening the city. Ramparts were rammed hard by elephants and planted with thorny and poisonous bushes to impede attackers. Moats were filled with water and sometimes lined with spikes. The article cites literary descriptions of cities such as Lankā, Indraprastha, Dvārakā and Conjeeveram, showing how fortification practices were widespread. By combining natural and artificial defences, ancient Indian cities achieved a high degree of security and demonstrated sophisticated urban planning.
Conclusion
The survey reveals that ancient Indian urban planners integrated geography and engineering to protect their cities. Natural barriers like rivers and mountains were augmented with walls, moats and forest belts, reflecting a pragmatic understanding of the landscape and the constant threat of warfare. Textual sources attest to the popularity of water and mountain forts, while treatises on statecraft prescribe detailed dimensions for artificial works. Together, these strategies show that defence was central to ancient Indian urbanism.