Most of the literary sources of ancient Indian history were predominantly religious and contain less factual data that can be considered as authentic historical source. Some of the oldest sources include the Puranas, the Vedas and epics like Ramayana and Mahabharata. These sources focus more on the civilisation and culture of that age instead of the political scenario. Rig veda, the earliest amongst the Vedas, provides information about the Aryans, their relocation to India, and their interaction with other clans. The Vedas generally offer detailed facts about the Aryan civilisation. The Puranas, which were prepared during the Gupta era, contain historical facts about the royal lineage and their reigns. Where as, the Upanishads notify about the religious part of the Vedic period. Furthermore, various Jain and Buddhist literatures and religious texts contain historical materials for reference. The Buddhist literatures, which were written in Pali, contained information about Lord Buddha and various kings of that era. The Jain texts, written in Prakit, provided facts about trade and traders in India. Buddhist Dwipavamsa, Mahavamsa and the Jain Parisistapravana are a few texts that supply some historical resources.
The Manu Smriti, Vishnu Smriti, Narada Smriti contained references regarding rules related to the law of the land and duties of kings and other bureaucrats. Arthashastra, a law book, written by Kautilya, states about the economic and legal issues present in the society, during the Maurya Empire. The grammar of Panini and Patanjali, Gargi Samhita also includes adequate historical sources.
Mudrarakshasa by Vishakhadatta gives a glance of Mauryan society. Malvikagnimitra speaks about the events of Pushyamitra Sunga`s era. Other important accounts that provide adequate historical information are, Gaudabaho by Bakpatiraja, which mentions the conquer of Yasovarman over Gauda, Banabhatta`s Harshacharita, that deal with the achievements of Harshvardhana, Ramacharita by Sandhyaakar Nandi, on the reign of Rampal, king of Pala dynasty, Vikramanka Charita by Bilhana, that states the history of Vikramaditya VI. Hem Chandra`s Dwasraya Kavya, Padmagupta`s Nabasahasanka Charita, Ballal`s Bhoja Prabandha, Nyaya Chandra`s Hammir Kavya are also worth mentioning. Rajatarangini written by Kalhana, is a valuable book which gives lot of information about the history of Kashmir and the kings of that period. Moreover works of the Sangam literature which is in Tamil provides information on economic and socio-political history during the period of the Pandyas, Cholas and Cheras.
Literary works by foreign visitors like Chinese, Romans and Greeks, who came to India, also act as Literary Sources of ancient Indian history. The Indica by Magasthenes, a Greek ambassador in the court of Chandragupta Maurya, includes various information of the era. A proper geographical account of India can be obtained from Ptolemy`s `Geography`. Naturalis Historia of Pliny gives an account of India`s flora and fauna and mineral resources and also mentions about trade relations between Italy and India. Where as, idea about India`s ports, harbours and trade and commerce conducted through the sea route can be obtained from Periplus of Erythraen. Moreover various texts by Chinese visitors like Hiuen Tsang, Fa Hien and others provide a detailed picture of Indian Buddhism.
Thus the various foreign or indigenous literary sources of ancient Indian history provide adequate knowledge on various aspects and thus provide support to reconstruct ancient Indian history.