Our ancestors lived in hunter-gatherer societies, after which man transitioned into agriculture and settlement; giving rise to the system of division of labour. Alongside this, another important social order to emerge was that of professional warriors, whose duty was to defend settlements against invaders.

In the subcontinent, the warriors surfaced as the second highest order of social ranking of the caste system and were known as Kshatriyas or professional fighters. In the battle of Mahabharata, when Arjun hesitated in fighting against his relatives who opposed him, Maharaj Krishna reminded him that as a Kshatriya, it was his dharma, or duty, to fight in the battle.

In the ancient city of Athens, military service was mandatory for every citizen whereas in Sparta, professional soldiers or hoplites trained in the art of warfare became famous for their bravery.

As the Romans built a great empire, they systematically organised their army and equipped it with new weapons. Strict rules and regulations were set and for the Romans, their army became an effective instrument to conquer vast territories, defeat powerful rivals and to expand their empire in the west as well as in the east.

After the fall of the Roman Empire, Europe was divided into small feudal states which fought wars with each other and pillaging became common. Consequently, a warrior class known as the knights materialised in Europe. They were patronised by the rulers, resided in their castles and shared food with them. The knights developed a strict code of chivalry, whereby when they were at war, they were to protect women and children and defend weak people.

When not at war, the knights occupied themselves with sword fighting and competitive warfare amongst each other to polish their skills. These tournaments were attended by rulers, courtiers and ladies from the nobility. In the beginning they fought with real weapons but when casualties occurred, their weapons were replaced by fake ones.

As these knights engaged in fighting, their war-play damaged agricultural fields. In an attempt to end the vicious circle of war, the clergy invited all knights to church where they were asked to pledge on holy relics of saints to renounce war. It was known as the truce and peace of God.

In the 11th century, when Pope Urban II declared a crusade against the Muslims, the knights found a new venue to fight. As a result of the crusade, two important organisations of knights known as Templars and Hospitallars emerged, answerable only to the pope. Being well-organised and disciplined, they fought against the Muslims with religious zeal; and accumulated enough wealth from the spoils of war to build their own castles.

Finally, threatened by their power, Philip IV, the ruler of France arrested the Templars. Their property was confiscated by the French state while they were tried on charges of heresy and burnt at stake. This is how their role in European history came to an end.

In the subcontinent, the Kshatriyas disappeared from history in the medieval period and were replaced by the Rajputs who undertook the task of fighting. The Rajputs observed strict rules and regulations as warriors and followed the ancient Hindu tradition of Jauhar; which was mass self-immolation by Rajput clans in order to avoid dishonour by the invading army. It was considered shameful to run away from the battlefield, whereas dying in the battlefield was deemed an honourable act. During the siege of Chittor, when Akbar observed the tradition, he was much impressed by the bravery of the Rajputs.

In the 15th century, the modern professional standing army was established in Europe, as a result of which the rulers became powerful and no longer had to rely on feudal armies if there was a crisis. In England, the parliament opposed it and passed the Bill of Rights in the glorious revolution of 1688, which forbade the king from keeping a standing army. However, in other European countries, the rulers kept standing armies and maintained their absolute power.

In modern times, every country maintains a professional standing army for its defense. However, in the third world countries, from time to time the army overthrows the democratic government and establishes a military dictatorship. There is a need to restructure the army and put it under civilian control in order to prevent any attempts of coup.