Already by the first century B.C., if not earlier, the trends which were to bring about the formation of an new form of Buddhism - the Mahayana - were well established in all schools of Buddhism. But it was probably not until the second century A.D. that it began to move towards becoming a separate school as opposed to a trend within the various existing schools. Some conflict occurred in the third century between those who accepted the Mahayana and those who did not, but eventually the two forms settled down to coexist together for many centuries. By the time of the visit of the first Chinese pilgrim (Fa-Hsien) in the early fifth century A.D., Indian monasteries (and often areas) were divided into those who studied only the pre-Mahayana scriptures and those who studied the writings of both traditions. Study of the Mahayana exclusively was probably never current in India.
A considerable and diverse literature remains from this period, although little is known of the contexts which produced these works. Certainly, they embody a number of tendencies. Some were concerned with mapping out the path to Buddhahood or presenting a transcendent vision of one or many Buddhas, with the historical Buddha tending to recede into the background. Others were more interested in putting forward a new vision of the philosophy of emptiness which had developed in the abhidharma schools of early Buddhism. Eventually, two major trends in systematic Mahayana thought developed. The first and probably the earliest of these was the Madhyamaka ‘Connected with the Middle’ or Sunyavada ‘Doctrine of emptiness’. Later, there developed a school which, although not apparently in conflict with the older school, tried to develop a more positive account of the Buddhist path. This was known as the Yogacara ‘Practice of Yoga’ or as the doctrine of Vijnaptimatrata ‘Information only’; it is often described as ‘idealism’, although in fact it does not consider mind to be ultimately real.
The classical form of the Mahayana developed over the period between the fifth and seventh centuries A.D. integrating teachings of these diverse origins into a complex and multivalent system. Both teachings deriving from various of the early schools as well as ideas and practices from different early Mahayanist groups went into this synthesis. But throughout the history of Indian Buddhism there was always a great deal of variety. In actual fact no simple account of this history can do it justice. What we know of it is mainly derived from literature, preserved either in Sutras - attributed to a Buddha or Bodhisattva, or in Sastras - systematic works usually ascribed to a human author. Theoretically, the former are revealed works which have priority, but in actual practice the historical process was not so simple. Sutras went on being written throughout the history of Indian Buddhism and were often influenced by previous Sastras. Moreover, most Sutras were revised from time to time to bring them up-to-date.
The last trend to develop was that which became the Mantrayana or ‘Vehicle of the Mantra’, later known also as the Vajrayana or ‘Vehicle of the Thunderbolt’. New texts, known as Tantras, adopted a much more magical and ritually orientated approach to Buddhism. Such works first appear, in a context which can be dated, in the seventh century A.D., but were probably the result of trends which had been developing for some centuries. Like the Mahayana before it, the Mantrayana generally developed along side earlier forms of Buddhism, coalescing with them rather than displacing them. It too developed a highly complex synthesis of many earlier practices with an elaborate theoretical substructure and was widely successful in the ensuing centuries.
Invasions, parlty motivated by Islamic zealotry, led to the systematic destruction of most large Indian monasteries in the twelfth century A.D. This was followed y some centuries of other pressures and, despite attempts to recover, Buddhism gradually disappeared from North India in the course of the thirteenth and fourteenth centuries. Theravada Buddhism seems to have maintained a presence in South India for some centuries longer, but it too had gone completely from the mainland (except perhaps in parts of Bangladesh) by the eighteenth century, if not earlier. Two forms of Indian Buddhism did survive to the present day - the Theravada in Ceylon and a type of Mahayana with a strong tantric emphasis in Nepal, while the present century has seen the reestablishment of various forms of Buddhism (both new and old) in India.