Coins first found their way into history as a way of payment 600 years before Christ. The Greek historian Herodotus[1] (484-425 BC) recorded that the first coins were minted by the kingdom of Lydia in Asia Minor under King Alyattes (619-560 BC). Aristotle on the other hand gives credit to the wife of King Midas of Phrygia (700 BC), Damodice daughter of Agamemnon of Cyme. Greeks were also involved in the minting of coins for Egyptians and others through Greek trading posts. The islands of Aegina, Miletus and Samos had trading post in the Nile Delta by the name of Naucratis providing concrete evidence of a minting industry.
When the Persians conquered Lydia in 546 BC, Persians adopted the concept of coinage. It was not until the middle of the fifth century when Phoenicians began minting coins. Minting of coins then spread to Sicily by the Carthaginian colonies. Romans were late to the game, it was not until 326 BC, when Roman began to mint their own coins.
Persians under the Archaemenid Empire (Cyrus the Great) and Greeks from Alexander the Great conquest of India, introduced coins to India.
These first coins of Lydia and Greece were made from a substance known as electrum[2], a naturally occurring alloy of silver and gold. These Lydian coins were based on the weight of a stater[3] (16.8 grams). They were minted in denominations based on their weight, they became known as half staters, third staters, sixth staters etc..etc..etc.
The earliest coins with a Greek legend on the coin reads 'I am the badge of Phanes'. Who was Phanes? We don’t know, he could have been a merchant, ruler or official…etc., What we know is he was placing his name to guarantee the quality of the coin, a practice that continues today with government coins.
China also began standardizing gold coins during the Qin Dynasty (221-207 BC), after the Qin the Han emperors followed the practice and included silver coins and “deerskin notes”, the first paper type currency.
[1] https://en.wikipedia.org/wiki/Herodotus
[2] http://www.britishmuseum.org/explore/themes/money/the_origins_of_coinage.aspx
[3] https://en.wikipedia.org/wiki/Stater