Trade has been going on for as long as humans have needed or wanted something that others had and they did not. Bartering for goods and trade in kind developed into more sophisticated forms of exchanges using commonly agreed commodity currencies such as bronze or copper ingots or even cowry shells. These were often only good for largescale trade deals though, and for smaller transactions, something else was needed: coinage. Coins were often introduced in ancient cultures as a convenient way to pay soldiers, but the idea quickly spread to civilian life.