a. Source of History:
Historians collect information from various trails for reconstructing history. The 'trails' are both written documents and archaeological evidences. These trails or clues taken together are known as the 'source materials of history'. The source materials are as essential part of history-writing. The source materials may differ from time to time and from country to country. Since the characteristics of ancient, medieval and modern times of a certain country differ, the source materials of these three periods are also different.
b. Importance of the Archaeological Source:
Recently historians attach much importance to the coins as source materials for reconstruction of ancient Indian history. For, the study of coins reveals such information which no other source does. For example, the metal or alloy of metals used in the coins give us an idea about the advancement made in metallurgy during the contemporary period.
Coins also throw light on the economic history. Distribution of coins is an indication that the economic activities under a particular king or kings had been extended to these areas. Again the coins in which names of kings have been mentioned enable us to know about the chronology of a ruling dynasty.
The Kushana kings had circulated different types of coins in which not only the name but also the year of accession has been mentioned. This has enabled us to fix the dates of various Kushana kings who ruled over India. The coins are a helpful in reconstruction the cultural history of a particular period.
Thus the importance of coins can hardly be minimized.
c. Accounts of the Foreign Travelers:
Though the Himalayas have separated India from the outside world it never proved to be an insurmountable barrier to establish cultural contact with other countries. In fact, from the earliest times travelers from different countries visited India. Though the travelers came with various purposes almost each one of them have written down their experiences in the form of books.
These accounts of the foreign travelers are important source of our- knowledge about ancient Indian history. Of the foreign accounts mention may be made of Indika by Megasthenes. Two important Chinese travelers were Fa- liien and Hiuen Tsang. It must, however, be remembered that the accounts of the foreign travelers are to be used cautiously.
For, some of the travelers made certain observations about India which are not correct. Possibly in some cases the foreigners had failed to assess correctly the Indian ways of life due to lack of their knowledge about the Indian languages, and hence the misrepresentation.