Tantric Buddhism was due to the mixture of Mahayanist teaching with aboriginal superstitions absorbed through the medium of Hinduism, though in some cases there may have been direct contact and mutual influence between Mahayanism and aboriginal beliefs. But as a rule what happened was that aboriginal deities were identified with Hindu deities and Buddhism had not sufficient independence to keep its own pantheon distinct, so that Vairocana and Târâ received most of the attributes, brahmanic or barbarous, given to Śiva or Kâli. The worship of the goddesses, described in their Hinduized form as Durgâ, Kâlî, etc., though found in most parts of India was specially prevalent in the sub-himalayan districts both east and west. Now Padma-Sambhava was a native of Udyâna or Swat and Târanâtha represents the chief Tantrists[314] as coming from there or visiting it. Hsüan Chuang[315] tells us that the inhabitants were devout Mahayanists but specially expert in magic and exorcism. He also describes no less than four sacred places in it where the Buddha in previous births gave his flesh, blood or bones for the good of others. Have we here in a Buddhist form some ancient legend of dismemberment like that told of Satî in Assam? Of Kashmir he says that its religion was a mixture of Buddhism with other beliefs.[316] These are precisely the conditions most favourable to the growth of Tantrism and though the bulk of the population are now Mohammedans, witchcraft and sorcery are still rampant. Among the Hindu Kashmîris[317] the most prevalent religion has always been the worship of Śiva, especially in the form representing him as half male, half female. This cult is not far from Śâktism and many allusions[318] in the Râjataranginî indicate that left-hand worship was known, though the author satirizes it as a corruption. He also several times mentions[319] Mâtri-cakras, that is circles sacred to the Mothers or tantric goddesses. In Nepal and Tibet tantric Buddhism is fully developed but these countries have received so much from India that they exhibit not a parallel growth, but late Indian Tantrism as imported ready-made from Bengal. It is here that we come nearest to the origins of Tantrism, for though the same beliefs may have flourished in Udyâna and Kashmir they did not spread much in the Panjab or Hindustan, where their progress was hindered at first by a healthy and vigorous Hinduism and subsequently by Mohammedan invasions. But from 700 to 1197 A.D. Bengal was remote alike from the main currents of Indian religion and from foreign raids: little Aryan thought or learning leavened the local superstitions which were infecting and stifling decadent Buddhism. Hsüan Chuang informs us that Bhaskaravarma king of Kâmarûpa[320] attended the fêtes celebrated by Harsha in 644 A.D. and inscriptions found at Tezpur indicate that kings with Hindu names reigned in Assam about 800 A.D. This is agreeable to the supposition that an amalgamation of Śivaism and aboriginal religion may have been in formation about 700 A.D. and have influenced Buddhism.
In Bihar from the eighth century onwards the influence of Tantrism was powerful and disastrous. The best information about this epoch is still to be found in Târanâtha, in spite of his defects.
He makes the interesting statement that in the reign of Gopâla who was a Buddhist, although his ministers were not (730-740 A.D.), the Buddhists wished their religious buildings to be kept separate from Hindu temples but that, in spite of protests, life-sized images of Hindu deities were erected in them.[321] The ritual too was affected, for we hear several times of burnt offerings[322] and how Bodhibhadra, one of the later professors of Vikramaśila, was learned in the mystic lore of both Buddhists and Brahmans. Nalanda and the other viharas continued to be seats of learning and not merely monasteries, and for some time there was a regular succession of teachers. Târanâtha gives us to understand that there were many students and authors but that sorcery occupied an increasingly important position. Of most teachers we are told that they saw some deity, such as Avalokita or Târâ. The deity was summoned by the rites already described[323] and the object of the performer was to obtain magical powers or siddhi. The successful sorcerer was known as siddha, and we hear of 84 mahâsiddhas, still celebrated in Tibet, who extend from Rahulabhadra Nâgârjuna to the thirteenth century. Many of them bear names which appear not to be Indian.
The topics treated of in the Tantras are divided into Kriyâ (ritual), Caryâ (apparently corresponding to Vinaya), Yoga, and Anuttara-yoga. Sometimes the first three are contrasted with the fourth and sometimes the first two are described as lower, the third and fourth as higher. But the Anuttara-yoga is always considered the highest and most mysterious.[324] Târanâtha says[325] that the Tantras began to appear simultaneously with the Mahayana sûtras but adds that the Anuttara-yoga tantras appeared gradually.[326] He also observes that the Âcârya Ânanda-garbha[327] did much to spread them in Magadha. It is not until a late period of the Pâla dynasty that he mentions the Kâlacakra which is the most extravagant form of Buddhist Tantrism.
This accords with other statements to the effect that the Kâlacakra tantra was introduced in 965 A.D. from Śambhala, a mysterious country in Central Asia. This system is said to be Vishnuite rather than Śivaite. It specially patronizes the cult of the mystic Buddhas such as Kâlacakra and Heruka, all of whom appear to be regarded as forms of Âdi-Buddha or the primordial Buddha essence. The Siddha named Pito is also described as the author of this doctrine,[328] which had less importance in India than in Tibet.
On the other hand Târanâtha gives us the names of several doctors of the Vinaya who flourished under the Pâla dynasty. Even as late as the reign of Râmapâla (? 1080-1120) we hear that the Hinayanists were numerous. In the reign of Dharmapâla (c. 800 A.D.) some of them broke up the great silver image of Heruka at Bodh-Gaya and burnt the books of Mantras.[329] These instances show that the older Buddhism was not entirely overwhelmed by Tantrism[330] though perhaps it was kept alive more by pilgrims than by local sentiment. Thus the Chinese inscriptions of Bodh-Gaya though they speak at length of the three bodies of Buddha show no signs of Tantrism. It would appear that the worship celebrated in the holy places of Magadha preserved a respectable side until the end. In the same way although Tantrism is strong in the literature of the Lamas, none of the many descriptions of Tibet indicate that there is anything scandalous in the externals of religion. Probably in Tibet, Nepal and mediæval Magadha alike the existence of disgraceful tantric literature does not indicate such widespread depravity as might be supposed. But of its putrefying influence in corrupting the minds of those who ought to have preserved the pure faith there can be no doubt. More than any other form of mixed belief it obliterated essential differences, for Buddhist Tantrism and Śivaite Tantrism are merely two varieties of Tantrism.
What is happening at Bodh-Gaya at present[331] illustrates how Buddhism disappeared from India. The abbot of a neighbouring Śivaite monastery who claims the temple and grounds does not wish, as a Mohammedan might, to destroy the building or even to efface Buddhist emblems. He wishes to supervise the whole establishment and the visits of pilgrims, as well as to place on the images of Buddha Hindu sectarian marks and other ornaments. Hindu pilgrims are still taken by their guides to venerate the Bodhi tree and, but for the presence of foreign pilgrims, no casual observer would suppose the spot to be anything but a Hindu temple of unusual construction. The same process went a step further in many shrines which had not the same celebrity and effaced all traces and memory of Buddhism.
At the present day the Buddha is recognized by the Brahmans as an incarnation of Vishnu,[332] though the recognition is often qualified by the statement that Vishnu assumed this form in order to mislead the wicked who threatened to become too powerful if they knew the true method of attaining superhuman powers. But he is rarely worshipped in propriâ personâ.[333] As a rule Buddhist images and emblems are ascribed to Vishnu or Śiva, according to sectarian preferences, but in spite of fusion some lingering sense of original animosity prevents Gotama from receiving even such respect as is accorded to incarnations like Paraśu-râma. At Bodh-Gaya I have been told that Hindu pilgrims are taken by their guides to venerate the Bodhi-tree but not the images of Buddha.
Yet in reviewing the disappearance of Buddhism from India we must remember that it was absorbed not expelled. The result of the mixture is justly called Hinduism, yet both in usages and beliefs it has taken over much that is Buddhist and without Buddhism it would never have assumed its present shape. To Buddhist influence are due for instance the rejection by most sects of animal sacrifices: the doctrine of the sanctity of animal life: monastic institutions and the ecclesiastical discipline found in the Dravidian regions. We may trace the same influence with more or less certainty in the philosophy of Śaṅkara and outside the purely religious sphere in the development of Indian logic. These and similar points are dealt with in more detail in other parts of this work and I need not dwell on them here.