Currency evolved from receipts representing stored grain in ancient Mesopotamia and Egypt. Coins were later developed using metals like silver and gold. Paper money originated as promissory notes representing deposits of coinage. A country determines which currency it uses, and currencies are identified with ISO codes combining the country code and currency name. The Indian rupee is the official currency of India, with coins and banknotes denominated in rupees. The rupee sign was created in 2010 to represent the currency. India has developed its own system of coins and banknotes over history and continues to determine currency policy.