As we have seen, the change which came over Buddhism was partly due to foreign influences and no doubt they affected most Indian creeds.  But the prodigious amplification of Hinduism was mainly due to the absorption of beliefs prevalent in Indian districts other than the homes of the ancient Brahmans.  Thus south Indian religion is characterized when we first know it by its emotional tone and it resulted in the mediaeval Sivaism of the Tamil country.  In another region, probably in the west, grew up the monotheism of the Bhagavatas, which was the parent of Vishnuism.

Hinduism may be said to fall into four principal divisions which are really different religions:  the Smartas or traditionalists, the Sivaites, the Vishnuites and the Saktas.  The first, who are still numerous, represent the pre-buddhist Brahmans.  They follow, so far as modern circumstances permit, the ancient ritual and are apparent polytheists while accepting pantheism as the higher truth.  Vishnuites and Sivaites however are monotheists in the sense that their minor deities are not essentially different from the saints of Roman and Eastern Christianity but their monotheism has a pantheistic tinge.  Neither sect denies the existence of the rival god, but each makes its own deity God, not only in the theistic but in the pantheistic sense and regards the other deity as merely an influential angel.  From time to time the impropriety of thus specially deifying one aspect of the universal spirit made itself felt and then Vishnu and Siva were adored in a composite dual form or, with the addition of Brahma, as a trinity.  But this triad had not great importance and it is a mistake to compare it with the Christian trinity.  Strong as was the tendency to combine and amalgamate deities, it was mastered in these religions by the desire to have one definite God, personal inasmuch as he can receive and return love, although the Indian feeling that God must be all and in all continually causes the conceptions called Vishnu and Siva to transcend the limits of personality.  This feeling is specially clear in the growth of Rama and Krishna worship.  Both of these deities were originally ancient heroes, and stories of love and battle cling to them in their later phases.  Yet for their respective devotees each becomes God in every sense, God as lover of the soul, God as ruler of the universe and the God of pantheism who is all that exists and can exist.

For some time before and after the beginning of our era, north-western India witnessed a great fusion of ideas and Indian, Persian and Greek religion must have been in contact at the university town of Taxila and many other places.  Kashmir too, if somewhat too secluded to be a meeting-place of nations, was a considerable intellectual centre.  We have not yet sufficient documents to enable us to trace the history and especially the chronology of thought in these regions but we can say that certain forms of Vishnuism, Sivaism and Buddhism were all evolved there and often show features in common.  Thus in all we find the idea that the divine nature is manifested in four forms or five, if we count the Absolute Godhead as one of them[19].