Write a short note on the use of coins as archaeological sources.
The study of coins is known as numismatics. Coins are a crucial source of information about the reign of kings, the extent of their empires, economic activity, trade, art and religion of any particular epoch. The metal or alloy used also give an indication as to the scientific progress achieved during that particular period. Many gold, silver, copper and lead coins have been found. The gold and copper coins found at relevant sites have provided important chunks of information about the famous Kushan empire.