• The migration of the Aryan-speaking peoples brought in the new
        Aryan elite.
     • Though the brief campaign of Alexander did not seriously disturb the
        centres of powers in the Punjab and Sind, the invasions of the Indo-
        Greeks, Sakas and Kushanas for two centuries definitely affected
        Indian society in the northern and western parts of the subcontinent.
     • The impact of the Huna invasions in the 5th century AD was felt as far
        as the heartland of the Ganges.
     • The migrations of people from Central Asia to northern and western
        India in the post-Gupta period produced an even greater impact.
Meaning and Features
Ancient Indian society is said to have consisted of four orders (chatur-varna);
a fifth order was included later. The first four were the Brahmin, the
Kshatriya, the Vaishya and the Sudra, of which the first three were regarded
as dvija or twice-born. The fifth order (panchamavarna) was later identified
with the untouchables. According to the Purusasukta in the mandala X of the
Rig Veda, the four orders were divinely created and arose out of the great god
Prajapati. This imbued the scheme with sanctity and authenticity.
     The concept of varna was closely associated with the concept of dharma
in the sense of a universal law. Thus, the varnadharma was the attempt to
establish a social law or a systematic functioning of society which would
ensure its well-being.
     To these was added the concept of the asramas or stages of life, giving
rise to the notion of varnas​rama-dharma which was sought to be justified
and perpetuated with the help of the theory of karma. In the later Vedic and
post-Vedic periods we hear of the four-fold division of life into
brahmacharin (student), grihastha (householder), vanaprastha (partial
retirement) and sannyasin (complete retirement or ascetic life). But this
concept of asramas was essentially    applicable to the members of the first two