The pattern of social classes in Hinduism is called the "caste system." The chart shows the major divisions and contents of the system. Basic caste is called varn.a, or "color." Subcaste, or jâti, "birth, life, rank," is a traditional subdivision of varn.a.
The Bhagavad Gita says this about the varn.as:
The works of Brahmins, Ks.atriyas, Vaishyas, and Shudras are different, in harmony with the three powers of their born nature. The works of a Brahmin are peace; self-harmony, austerity, and purity; loving-forgiveness and righteousness; vision and wisdom and faith.
These are the works of a Ks.atriya: a heroic mind, inner fire, constancy, resourcefulness, courage in battle, generosity and noble leadership.
Trade, agriculture and the rearing of cattle is the work of a Vaishya. And the work of the Shudra is service.
There are literally thousands of subcastes in India, often with particular geographical ranges and an administrative or corporate structure. When Mahâtmâ Gandhi wanted to go to England to study law, he had to ask his subcaste for permission to leave India. ("Gandhi" means "greengrocer" -- from gandha, "smell, fragrance," in Sanskrit -- and that should be enough for a good guess that Gandhi was a Vaishya.) Sometimes it is denied that the varn.as are "castes" because, while "true" castes, the jâtis, are based on birth, the varn.as are based on the theory of the gun.as (the "three powers" mentioned in the Gita). This is no more than a rationalization: the varn.as came first, and they are based on birth. The gun.as came later, and provide a poor explanation anyway, since the gun.a tamas is associated with both twice born and once born, caste and outcaste. Nevertheless, the varn.as are now divisions at a theoretical level, while the jâtis are the way in which caste is embodied for most practical purposes. Jâtis themselves can be ranked in relation to each other, and occasionally a question may even be raised about the proper varn.a to which a particular jâti belongs.
Associated with each varn.a there is a traditional color. These sound suspiciously like skin colors; and, indeed, there is an expectation in India that higher caste people will have lighter skin -- although there are plenty of exceptions (especially in the South of India). This all probably goes back to the original invasion of the Arya, who came from Central Asia and so were undoubtedly light skinned. The people already in India were quite dark, even as today many people in India seem positively black. Apart from skin color, Indians otherwise have "Caucasian" features -- narrow noses, thin lips, etc. -- and recent genetic mapping studies seem to show that Indians are more closely related to the people of the Middle East and Europe than to anyone else. Because Untouchables are not a varn.a, they do not have a traditional color. I have supplied blue, since this is otherwise not found, and it is traditionally used for the skin color of Vis.n.u and his incarnations. Chief among those is Kr.s.n.a (Krishna), whose name actually means "black" or "dark," but he is always shown blue rather than with some natural skin color. The first three varn.as are called the twice born. This has nothing to do with reincarnation. Being "twice born" means that you come of age religiously, making you a member of the Vedic religion, eligible to learn Sanskrit, study the Vedas, and perform Vedic rituals. The "second birth" is thus like Confirmation or a Bar Mitzvah. According to the Laws of Manu (whose requirements may not always be observed in modern life), boys are "born again" at specific ages: 8 for Brahmins; 11 for Ks.atriyas; and 12 for Vaishyas. A thread is bestowed at the coming of age to be worn around the waist as the symbol of being twice born. The equivalent of coming of age for girls is marriage. The bestowal of the thread is part of the wedding ceremony. That part of the wedding ritual is even preserved in Jainism. Ancient Iran also had a coming of age ceremony that involved a thread. That and other evidence leads to the speculation that the three classes of the twice born are from the original Indo-European social system -- the theory of George Dumézil. Even the distant Celts believed in three social classes. The three classes of Plato's Republic thus may not have been entirely his idea. Although there must have been a great deal of early intermarriage in India, nowhere did such an Indo-European social system become as rigid a system of birth as there. The rigidity may well be due to the influence of the idea of karma, that poor birth is morally deserved.
According to the Laws of Manu, when the twice born come of age, they enter into the four âshramas or "stages of life."
The first is the brahmacarya, or the stage of the student (brahmacârin). For boys, the student is supposed to go live with a teacher (guru), who is a Brahmin, to learn about Sanskrit, the Vedas, rituals, etc. The dharma of a student includes being obedient, respectful, celibate, and non-violent. "The teacher is God." For girls, the stage of studenthood coincides with that of the householder, and the husband stands in the place of the teacher. Since the boys are supposed to be celibate while students, Gandhi used the term brahmacâri to mean the celibate practitioner that he thought made the best Satyagrahi, the best non-violent activist.
The second stage is the gârhastya, or the stage of the householder, which is taken far more seriously in Hinduism than in Jainism or Buddhism and is usually regarded as mandatory, like studenthood, although debate continued over the centuries whether or not this stage could be skipped in favor of a later one. This is the stage where the principal dharma of the person is performed, whether as priest, warrior, etc., or for women mainly as wife and mother. Arjuna's duty to fight the battle in the Bhagavad Gita comes from his status as a householder. Besides specific duties, there are general duties that pay off the "three debts": a debt to the ancestors that is discharged by marrying and having children; a debt to the gods that is discharged by the household rituals and sacrifices; and a debt to the teacher that is discharged by appropriately teaching one's wife or children. The third stage is the vânaprastya, or the stage of the forest dweller. This may be entered into optionally if (ideally) one's hair has become gray, one's skin wrinkled, and grandchildren exist to carry on the family. Husbands and wives may leave their affairs and possessions with their children and retire together to the forest as hermits. This does not involve the complete renunciation of the world, for husbands and wives can still have sex (once a month), and a sacred fire still should be kept and minimal rituals performed. This stage is thus not entirely free of dharma. The Forest Treatises were supposed to have been written by or for forest dwellers, who have mostly renounced the world and have begun to consider liberation. I am not aware that forest dwelling is still practiced in the traditional way. The modern alternatives seem to consist of the more stark opposition between householding and becoming a wandering ascetic.
The fourth stage is the sannyâsa, or the stage of the wandering ascetic, the sannyâsin (or sâdhu). If a man desires, he may continue on to this stage, but his wife will need to return home; traditionally she cannot stay alone as a forest dweller or wander the highways as an ascetic. The sannyâsin has renounced the world completely, is regarded as dead by his family (the funeral is held), and is finally beyond all dharma and caste. When a sannyâsin enters a Hindu temple, he is not a worshiper but one of the objects of worship. Not even the gods are sannyâsins (they are householders), and so this is where in Hinduism, as in Jainism and Buddhism, it is possible for human beings to be spiritually superior to the gods. It has long been a matter of dispute in Hinduism whether one need really fulfill the requirements of the Laws of Manu (gray hair, etc.) to renounce the world. There are definitely no such requirements in Jainism or Buddhism. The Buddha left his family right after his wife had a baby, which would put him in the middle of his dharma as a householder. Jainism and Buddhism thus developed monastic institutions, but these did not really develop as such in Hinduism. The four stages of life may, somewhat improbably, be associated with the four parts of the Vedas: the sam.hitâs with the stage of the student, who is particularly obligated to learn them; the brâhman.as with the stage of the householder, who is able to regulate his ritual behavior according to them; the âran.yakas with the stage of the forest dweller, who regulates his ritual behavior according to them and who begins to contemplate liberation; and finally the upanis.ads with the stage of the wandering ascetic, who is entirely concerned with meditation on the absolute, Brahman. The twice born account for about 48% of Hindus. The rest are Shudras and Untouchables. The Shudras may represent the institutional provision that the Arya made for the people they already found in India. The Shudras thus remain once born, and traditionally are not allowed to learn Sanskrit or study the Vedas. Their dharma is to work for the twice born. But even below the Shudras are the Untouchables, who are literally "outcastes," without a varn.a, and were regarded as "untouchable" because they are ritually polluting for caste Hindus. Some Untouchable subcastes are regarded as so polluted that members are supposed to keep out of sight and do their work at night: They are called "Unseeables." In India, the term "Untouchable" is now regarded as impolite or politically incorrect (like Eta in Japan for the traditional tanners and pariahs). Gandhi's Harijans ("children of God") or Dalits ("downtrodden") are prefered, though to Americans "Untouchables" would sound more like the gangster-busting federal agent Elliot Ness from the 1920's. Why there are so many Untouchables (15%-20% or so of Hindus) is unclear, although caste Hindus can be ejected from their jâtis and become outcastes and various tribal or formerly tribal people in India may never have been properly integrated into the social system. When Mahâtmâ Gandhi's subcaste refused him permission to go to England, as noted above, he went anyway and was ejected from the caste. After he returned, his family got him back in, but while in England he was technically an outcaste. Existing tribal people, as well as Untouchables, are also called the "scheduled castes," since the British drew up a "schedule" listing the castes that they regarded as backwards, underprivileged, or oppressed. The Untouchables, nevertheless, have their own traditional professions and their own subcastes. Those professions (unless they can be evaded in the greater social mobility of modern, urban, anonymous life) involve too much pollution to be performed by caste Hindus:
(1) dealing with the bodies of dead animals (like the sacred cattle that wander Indian villages) or unclaimed dead humans,
(2) tanning leather, from such dead animals, and manufacturing leather goods, and
(3) cleaning up the human and animal waste for which in traditional villages there is no sewer system. Mahâtmâ Gandhi referred to the latter euphemistically as "scavenging" but saw in it the most horrible thing imposed on the Untouchables by the caste system. His requirement on his farms in South Africa that everyone share in such tasks comes up in an early scene in the movie Gandhi. Since Gandhi equated suffering with holiness, he saw the Untouchables as hallowed by their miserable treatment and so called them "Harijans" (Hari=Vis.n.u). Later Gandhi went on fasts in the hope of improving the condition of the Untouchables, or at least to avoid their being politically classified as non-Hindus. Today the status of the Shudras, Untouchables, and other "scheduled castes," and the preferential policies that the Indian government has designed for their advancement ever since Independence, are sources of serious conflict, including murders and riots, in Indian society.
Samudragupta is considered as one of the greatest rulers in Indian history. He is also compared to Alexander or Napoleon as a conqueror. He performed Ashwamedha Yajna (horse sacrifice) after defeating nine kings in the north and twelve kings in the south to underline the importance of his conquest of almost the whole of India. He also assumed the title of Maharajadhiraja (King of Kings) and Chakravartin (Universal Monarch).
Many people were agriculturists. They grew rice, wheat, barley, pulses, cotton and vegetables. Others were artisans. They specialised in different crafts, as in the earlier period. Textiles, wooden, and ivory objects, perfumes, jewellery from semi-precious stones, items of iron and copper and the shining black pottery described earlier, were among 
India, 326 BC: Alexander moves through the dense jungles of Ohind. Then, having crossed the Indus river and secured the help of the Ambhi, king of Taxila, Alexander marches on to the Jhelum. The Pauravan king with an army of 30,000 soldiers, horses and elephants provided fierce resistance but was eventually defeated.