Of the non-Buddhist textural sources originating in India, the earliest, by far, are the Vedas, with the Rig Veda being the earliest. The four Vedas contain descriptions of early religious beliefs, rituals, medical practices, and heroic stories of kings. Together the Vedas are often seen as the foundation for the rest of Indian history, referred to in the subsequent religious literature of Brahmanism, Hinduism, Jainism, and Buddhism. The rest of the primary source material from India was written in the first millennium GE. These sources include the Hindu epics, the Mahabharata and Ramayana, a more scholastic text on statecraft (the Arthashastra), and a collection of histories and religious stories called the Puranas. In the peninsula, Tamil Sangam literature consists of collections of poems. All of these literary sources are believed to refer to the first millennium bge but were composed in the first millennium GE. The earliest available versions of the Ramayana and the Mahabharata date to the second or third centuries GE (Thapar 2002). Trautmann (1971) and Thapar (2002) argue that the Arthashastra, though typically ascribed to Kautilya, a third-century bge royal advisor, was likely collated only in the second or third century GE. The Sangam literature of Tamil Nadu is more difficult to date but most likely was composed in the first half of the first millennium GE (Basham 1967; Thapar 2002).
The Puranas, a collection of histories, myths, stories, and poems, are particularly difficult to date and interpret. They appear to have been collated in the mid-first millennium GE (Basham 1967; Singh 2008; Thapar 2000, 2002). As historical documents, the Puranas are notoriously difficult to use (Kosambi 1965; Ray 1986; Thapar 2000; Trautmann and Sinopoli 2002). The historical and mythical components are mixed to such a degree that determining strict chronological and historical data is often i mpossible. In several key areas—the dynastic lists of the Satavahana state, for example—the Puranas present multiple versions of the same event. While problematic for developing chronologies, the Puranas do provide a window into the social patterns of the early India, as long as it is remembered that this view is filtered through the mid-first millennium GE context in which the Puranas were written (see Thapar 2000 for a more detailed investigation of the historical value of the Puranas). In this way, the Puranas are no better, or worse, than the other early literary sources from India.
A final source for the study of Indian Buddhism are mostly Persian accounts recording the military campaigns of Central Asians who began raiding northwest India in the beginning of the second millennium GE. By the end of the twelfth century GE, Central Asian Turks established the first Indo-Muslim state, the Delhi Sultanate, in North India. As will be discussed at length in Chapter 7, under the threat of the Turkish armies, most of the Buddhist monasteries in the Gangetic Plain were abandoned in the early thirteenth century CE. As with other historical accounts, the Persian sources must be read carefully (Eaton 2000). While some were written at the time of the conquests, many others are retrospective accounts written centuries later. Even those Persian accounts that date to the periods they refer were often hagiographies of particular rulers, valorizing their military accomplishments and overstating their Islamic faith. That said, when read carefully, Persian accounts provide genuine insight on the decline and collapse of monastic Buddhism in India.