With the invasion of the Afghans into the country there was total standoff regarding the military quotient. Small principalities flourished in their full glory, completely oblivious to the common danger. If there were confederations on certain occasions to meet the invaders they just swelled the numbers and weight without adding anything substantial to their ranks. They were defeated by comparatively smaller armies. With their dynamic leadership and new tactics the invaders established their superiority. The two battles of Prithviraj Chauhan against Muhammad Ghori are a case in point. In spite of his better organised army, Ghori was beaten by the numerically superior forces of the Indians. But soon he returned. For some time, the Afghans remained aliens with their foreign armies and the local military classes did not own them. The Rajputs gave the Afghans a tough fight and were the main opponents to the new order. Muhammad Bin Tughlaq was the first Afghan ruler of Delhi who undertook campaigns beyond the frontiers of India. At one time he is reported to have collected an army of 370,000 men for an expedition against Khorasan. All the troops were paid in advance for a whole year. The so called Chinese expedition was also undertaken by Muhammad Tughlaq. This was in fact against some of the hill tribes of the western Himalayas. Infantry and cavalry continued to form the main components.
According to the contemporary histories and records of the Afghan period, the Indian Army during Afghan rule was divided into four different kinds. The first kind of soldiers was the slave soldiers, like the Janissaries, who were mainly drawn from youths captured from peripheral areas. Though most of these soldiers were Muslims, the Hindus were also included among them and the Afghan Sultans trained these soldiers for service and loyalty only to the sultan. There is no strong proof available for the numbers of the slave soldiers. However, according to one account, the sultan possessed fifty thousand slave boys. The second kind of soldiers was the foreign soldiers, who came from outside India. These soldiers were largely Turks and Afghans and they were mainly attracted by the prospect of loot. The third kind of soldiers was the Muslim mercenary troops, who were referred to as ghazis. The Muslim mercenary troops opportunistically volunteered for service in the sultan's army on the eve of campaigns.
The Hindu troops were the fourth and final kind of soldiers and almost all the Hindu soldiers were the foot soldiers or workers, serving the military in the field. According to the histprical accounts available, the total number of soldiers serving the sultan consistently was between 475,000 and 900,000. At that time, the number of cavalry troopers available was carefully monitored by a system of branding horses and keeping detailed written descriptions of individual soldiers and the soldiers had to present themselves for review when serving the sultan. This branding and detailed description system did prevent the horses and men from being presented more than once by their commanders, and the commanders received payments from the sultan on the basis of the number of men and horses they presented at muster. The commanders were used to present their troops in groups of ten for facilitating the counting. This system gives an idea about the vastness of the Indian Army during Afghan rule. The revenue necessary to support troop strengths of this size has been estimated to have been the equivalent of 50 percent of the agricultural revenue of the sultans.
According to historians, the Afghan sultans of Delhi did possess seventy thousand horses for their cavalry soldiers. Though some of the scholars are sceptic about such vastness of the Indian Army during Afghan rule, the numbers can be proved as demographically reasonable. If the combined population of Asiatic Turkey, the Caucasus, Russian Turkestan, Iran, Iraq, and Afghanistan in the twelfth century of 18-19 million is taken into consideration, then these numbers look to be logical. According to the estimate of the historians, the population of the Indian subcontinent during that period was between 83 and 86 million. However, in spite of the scepticism of some of the scholars, a picture of the vastness and strength of the Indian Army during Afghan rule can easily be drawn. Another thing should also be taken into consideration that the total available mounted strength was not the same as the strength that was maintained as a standing army.
Some of the historians say that the slave soldiers, who owed their loyalty exclusively to the sultan and were paid only by him, were actually some very small fraction of the military strength on which the sultan depended. They say that in fact, the bulk of the Indian Army during Afghan rule was temporarily drawn from the host societies of central, south, and southwest Asia as needed for battle. The Afghan Sultans dispersed those soldiers in garrisons within the sultanate under the control of provincial governors. The Indian Army during Afghan rule was heterogeneous in nature, and it comprised Hindus and Muslims, Indians, Afghans, Turks, and also others. Though, the Indian Army was not a highly trained or disciplined army, the Afghan sultans provided some training that were mainly focused on the development of individual skills, not unit performance. In fact, the striking power of the armies of the Afghan sultans was mainly the ferocity of the individual warriors.