Military architecture in the second half in ancient India was largely borrowed from ancient European warring strategies. The early 10th to 15th centuries for example had seen widespread diffusion of empires, facilitating structures that would safeguard army men and their wars. And such fascinating annals on the primeval culture have been broadly explained in Indian historical sections. Although Indian history owns a considerable amount of fascinating studies on separate forts, all of these generally incline to focus on the aesthetic, art-historical aspects and much less on functional characteristics. The same can be spoken for numerous studies on temples and cities. From the point of view of an art historian, their defensive systems are the least motivating. Leaving the art historians aside, (which are at times excellent), descriptive accounts of early archaeological surveys as well as the more modern fieldwork on sites like Hissar, Nagaur, Firozabad, Vijayanagara and Daulatabad are worth mentionable to comprehend military architecture in ancient India. But apart from these more segregated studies; Jean Deloche's enthralling work on pre-Islamic fortifications in southern India is the first factual attempt at a more comprehensive analysis.
On the whole, it appears that a steady transformation in ancient Indian military architecture did take place. Although, most dramatically, the transformation could be noticed during the early Muslim period, approximately from the thirteenth to the fifteenth centuries. This transformation in ancient Indian military architecture could have been the outcome of superior siege technology, particularly the invention of new gunpowder devices and ballistae, which followed India's intensified interaction with Central Asia and Iran. What could then be witnessed, for instance, was the appearance of round bastioned towers which might have been concentrated against sappers who would have found trouble-free cover at the tower's corners. In other places, earlier massive walls were supplied with inner vaulted chambers and depots, as well as machicolations and barbicans. These stunning military architectures greatly improved the ability to provide counter-fire against attackers alongside the walls. To reimburse for the building of these inner chambers and gangways, walls became much thicker and were more sturdily built. At some other places, like at Tughlaqabad in Delhi, the ever-increased threat of mining and trebuchets might also have led to the building of, often double-line, projecting bastions. Such bastions were also often provided with a base of scraped rock and sloping bolster plinths. The moats in front of these were additionally deepened and widened.
Whatever were the reasons for these adaptations, a fundamental aspect was mostly forgotten when dealing with military architecture in ancient India. That aspect was that any siege operation called for a gargantuan logistical performance, especially from the expansionist armies of northern India which had to defend very extensive supply-lines. Thus, apart from some upheavals in siege technology, the aspect of possible logistical developments were taken into account as well, keeping the future perilous prospects in mind. The various demanding properties were the varying availability of cash and various means of transport, such as horses, dromedaries and oxen.
The introduction of the true cannon during the second half of the fifteenth century engendered some additional changes under military architecture in ancient India. These changes primarily involved the making of additional portholes with enhanced covering, as well as the levelling of towers and walls to make room for the installation and movement of guns. These changes increased the firing power of the defenders and made it even more bothersome for the besiegers to draw near the walls. The early medieval forts long continued to dictate over the Indian countryside. It even appears that forts re-emerged as the strongholds of new martial elites of Afghans, Rajputs, Marathas, Nayakas and others. They not only served as defensive bulwarks against persistent trespassing and nomadic war-bands, but also, more importantly, as nerve centres of agrarian and commercial exploitation.
Military architecture in ancient India gradually looked towards a more European side, making use of sophisticated weaponry. Although firearms were introduced simultaneously with cannon, they became widely used only during the seventeenth century. India during those times possessed specialised groups of sharp-shooting infantrymen, as compared to the Swiss and German Lands-knechte in Europe. And these skilled shooters often came from the mawash, i.e. the less-fertile environs of sedentary society such as the Mawalis from the Western Ghats or the Berars from the eastern jungles of the Deccan. Or perhaps even more important, the shooters arrived from areas that were beyond the range of action of large-scale cavalry armies, mostly at the fringe of both agrarian fields and pastures. Warfare in these fringe areas followed different strategic and tactical rules and demanded an assortment of weaponry.
Both at home and in Foreign Service, these 'infantry' units, a new entrant in the ancient Indian military architecture, often served behind trenches or other cover and hardly in the open field. Employing these devises, they kept up a continuous fire. However, these infantry units cannot be considered the Indian counterparts of the drilled and well-trained squares or tercios of musketeers and pike men. For a very long time, the standard Indian musket remained the home-made matchlock musket, which most likely had entered South Asia from Eastern Europe through Middle Eastern channels. Indian infantry did not, until rather late, take up the flintlock mechanism. This might partly be due to the lack of first-rate flints but, more importantly, adopting flintlocks only made sense when engaged by drilled units. Only during the second half of the eighteenth century, Indian armies, this time trained by European officers, took up both flintlocks and socket bayonets. It is only from this time onwards that infantry became the most powerful tool of war in India. What made the noteworthy difference was the crucial combination of professional drill with modern fast-firing firearms.
It should be stressed here that the emergence of 'modern' infantry and artillery was not an exclusively European achievement. The radical tactical changes during the eighteenth century were also the outcome of a process of interactive learning between European and Asian armies. Several historians for instance, pointed out the very competent, often superior, performances of the Maratha and Afghan armies, compared to their counterparts of the British East India Company. Historians also took issue against Surendranath Sen. It is sometimes claimed that the Marathas should never have abandoned the speed and mobility of 'guerrilla' tactics. That the reason they were ultimately defeated by the British was their shift to the more positional warfare of infantry and artillery, a department where the British were much superior. The convincing rising graph is demonstrated by the effectiveness of late eighteenth-century and early nineteenth-century Maratha artillery and infantry against their more primitive British rivals at times. An infantry revolution however did not occur in South Asia before the second half of the eighteenth century. The rapid changes after approximately 1750 were sparked off by the extraordinary European example at Plassey and other battlefields, but were developed further in the ongoing interplay between European and Indian armies.
Apart from the technological advantage, the sharp difference between British and Indian war aims, based on two different political systems, decided the outcome of the colonial wars. Returning to the theme of military revolution, it can be stated that India very cautiously adjusted to the enhanced capabilities of artillery and infantry, perhaps most borne out by the belated or failed adoption of the trace italienne and the flintlock. On the other hand, military architecture in ancient India was fully part of the earlier revolution involving the war-horse. Besides, the country's military architecture was transformed, most probably following better siege technology and logistics. Until the second half of the eighteenth century, not gunpowder, but the horse and the fort remained the prerequisite of Indian warfare and state formation. It appears that during that time infantry, unless drilled in the European manner, could hardly make an impression against the sheer size of Central and South Asian cavalry armies. The latter consisted of light mounted archers and heavy shock-troopers protected by bullet and arrow proof body armour.